feat: v0.8.0 edit and save files with conflict detection

- devdesk attach --fs-write SESSION PATH BYTES BASESHA|new: streamed like uploads, temp file in the same folder, sha re-check (conflict reply instead of overwriting), mode/owner kept, atomic mv; new files with folders, never outside the session folder or through a symlink out of it. - Editor: editable CodeMirror for UTF-8 text, dirty tracking, Ctrl+S, Save/Revert, conflict dialog with a disk-vs-yours diff, changed-on-disk banner, drafts in localStorage (flushed on pagehide), close/leave guards, New file. - Upload streaming factored into streamIn(), shared by uploads and saves. Closes #20 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
fix: old links never re-create ended sessions
2026-10-10 20:10:45 -04:00 · 2026-10-10 19:57:52 -04:00 · 2026-10-08 01:50:50 -04:00 · 2026-10-08 01:40:47 -04:00 · 2026-10-08 01:16:37 -04:00
21 changed files with 2994 additions and 58 deletions
@@ -8,7 +8,7 @@ SHAREDIR   := $(PREFIX)/share/devdesk
 TTYD_ARCH  ?= x86_64

 SHELL_SCRIPTS := bin/devdesk $(wildcard libexec/devdesk-*) scripts/fetch-ttyd.sh debian/devdesk.postinst debian/devdesk.postrm
-WEB_SOURCES   := web/build.mjs web/index.template.html web/styles.css $(wildcard web/src/*.js) \
+WEB_SOURCES   := web/build.mjs web/index.template.html web/styles.css $(wildcard web/src/*.js) $(wildcard web/editor/*.js) \
                 vendor/web_template/base.css debian/changelog

 .PHONY: all lint test install clean sync-template
@@ -26,7 +26,7 @@ build/ttyd: vendor/ttyd/VERSION vendor/ttyd/SHA256SUMS scripts/fetch-ttyd.sh
 	@touch $@

 lint: node_modules/.package-lock.json
-	npx eslint --max-warnings 0 --ext .js,.mjs web/src web/build.mjs tests/protocol.test.mjs
+	npx eslint --max-warnings 0 --ext .js,.mjs web/src web/editor web/build.mjs tests/protocol.test.mjs
 	shellcheck -x $(SHELL_SCRIPTS)
 	jq empty share/claude-settings.json

@@ -41,8 +41,11 @@ install: all
 	install -m 0755 libexec/devdesk-picker libexec/devdesk-claude-run libexec/devdesk-session-hook \
 		libexec/devdesk-tmux-ready libexec/devdesk-serve libexec/devdesk-statusline \
 		libexec/devdesk-deploy libexec/devdesk-state-hook libexec/devdesk-notify-matrix $(DESTDIR)$(LIBDIR)/
+	install -m 0644 libexec/devdesk-files.sh $(DESTDIR)$(LIBDIR)/devdesk-files.sh
 	install -m 0755 build/ttyd $(DESTDIR)$(LIBDIR)/bin/ttyd
 	install -m 0644 dist/index.html share/tmux.conf share/claude-settings.json $(DESTDIR)$(SHAREDIR)/
+	install -d $(DESTDIR)$(SHAREDIR)/assets
+	install -m 0644 dist/assets/editor.js $(DESTDIR)$(SHAREDIR)/assets/editor.js
 	install -m 0644 etc/env $(DESTDIR)$(SYSCONFDIR)/devdesk/env

 clean:
@@ -46,6 +46,8 @@ The tmux server runs in its own unit, so every Claude process lives in **that**
  - **Ask Claude** types an investigation prompt into the current session without sending it.
  - Configure `DEVDESK_GRAFANA_URL`, plus a Viewer token in `DEVDESK_GRAFANA_TOKEN_FILE`.
 - **Repo / CI panel:** branch, ahead/behind, uncommitted changes, HEAD's Gitea CI status and open PRs for the session's folder. When CI fails, **Ask Claude to fix CI** types a prompt to read the failed job's log.
+- **Files** (Ctrl+Shift+E), laid out like VS Code: an explorer tree (git colours, gitignored entries dimmed) and an editor with tabs (a click opens a preview tab, a double-click keeps it), **Go to file** (Ctrl+P in the pane), markdown previews (sanitized, with relative images), images, and a Changes view of uncommitted files with line counts, a **C** badge on files Claude edited, and diffs against HEAD. **@Claude** types `@path` into the prompt. Tabs and open folders are remembered per session. Paths can't leave the session folder.
+  - **Editing:** text files are editable; ● marks unsaved tabs; Ctrl+S (or Save) writes atomically and keeps the file's mode and owner. If the file changed on disk since you opened it (Claude edited it), saving asks: Compare (a diff of disk vs yours), Overwrite or Cancel; a change on disk while you edit shows a banner instead of replacing your text. Unsaved edits are kept as drafts in the browser, so a reload or a session switch doesn't lose them. ＋ creates a file (folders as needed). The editor bundle (`/usr/share/devdesk/assets/editor.js`) loads over ttyd the first time and is cached by the browser.
 - **Context:** a Claude `statusLine` command (`devdesk-statusline`) snapshots each session's model, context-window use and cost to `/var/lib/devdesk/context/<session>.json`. The Sessions panel shows it as a bar (cost in the tooltip), and Claude's own footer shows a one-line summary.
 - **Light mode:** the terminal switches palettes with the page. DevDesk starts Claude with its `dark-ansi` theme so Claude draws with the terminal's 16 colours, and the light palette maps bright white to ink; tmux and the status line use ANSI colours too. A session picks up Claude's theme the next time Claude starts in it (`/exit`, then ⏎ resumes the same conversation).
 - **Phone:** a key bar replaces the shortcut hints (Esc, Tab, ⇧Tab, ^C, ↑, ↓, ⏎, Claude/Shell window), and the panels open as a drawer.
@@ -62,6 +64,7 @@ The tmux server runs in its own unit, so every Claude process lives in **that**
 | Shift+drag | Native browser selection (plain drag goes to tmux copy-mode, which copies via OSC 52) |
 | Ctrl+Shift+C / V | Copy selection / paste |
 | Ctrl+Shift+P | Command palette (also the ⌕ button) |
+| Ctrl+Shift+E | Files pane (Esc: back, then close) |

 The **☀/◐** button switches light and dark mode (saved per browser, shared with the other web_template apps' `lt_theme` preference). Text size, desktop notifications (with a mute), the keyboard shortcuts sheet and fullscreen are in the **⋯** menu; everything is also in the command palette. In Chromium, fullscreen also captures Ctrl+W/Ctrl+T, which browsers otherwise keep for themselves.

@@ -17,6 +17,8 @@ set -euo pipefail

 # shellcheck source=libexec/devdesk-lib.sh
 . "${DEVDESK_LIBEXEC:-/usr/lib/devdesk}/devdesk-lib.sh"
+# shellcheck source=libexec/devdesk-files.sh
+. "$DEVDESK_LIBEXEC/devdesk-files.sh"

 usage() {
    sed -n '2,12s/^# \{0,1\}//p' "$0"
@@ -316,6 +318,13 @@ cmd_attach() {
        dd_linger
        return
        ;;
+    --fs-list | --fs-find | --fs-read | --fs-write | --git-status | --git-show | --asset)
+        local action=${1#--}
+        shift
+        "cmd_${action//-/_}" "$@"
+        dd_linger
+        return
+        ;;
    --new | --rename | --end)
        local action=${1#--}
        shift
@@ -1,3 +1,94 @@
+devdesk (0.8.0) bookworm; urgency=medium
+
+  * Edit and save files in the Files pane (#20):
+    - Text files open editable; ● marks unsaved tabs; Ctrl+S or Save writes
+      through `devdesk attach --fs-write`: a temp file in the same folder,
+      mode and owner kept, swapped in with mv.
+    - Conflict detection: the save carries the sha256 of the version you
+      opened; if Claude (or anyone) changed the file since, nothing is written
+      and you choose Compare (diff of disk vs yours), Overwrite or Cancel.
+    - A file that changes on disk while you edit it shows a banner (Compare,
+      Reload, Keep mine) instead of replacing your text; clean files still
+      reload in place.
+    - Unsaved edits are mirrored to the browser as drafts (flushed when the
+      page closes), so a reload, a crash or a session switch doesn't lose
+      them; a draft for a file that changed since offers Compare/Restore/
+      Discard.
+    - Closing a tab with unsaved changes asks Save / Don't save / Cancel;
+      leaving the page warns.
+    - ＋ New file (missing folders are created; never outside the session
+      folder, and never through a symlink out of it).
+    - Markdown previews show unsaved Source edits. Latin-1 files stay
+      read-only.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Sat, 10 Oct 2026 20:09:49 -0400
+
+devdesk (0.7.3) bookworm; urgency=medium
+
+  * Fix (#38): links that mean "go to that session" no longer re-create one
+    that was ended. The 🔔 inbox, the session switcher, palette switches, the
+    "needs you" chip and Matrix links (now ?arg=NAME&existing=1) open sessions
+    existing-only; an ended one shows "NAME has ended" with an explicit
+    "Start NAME again". Inbox entries for ended sessions are marked as such,
+    and entries older than 7 days are dropped.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Sat, 10 Oct 2026 19:57:52 -0400
+
+devdesk (0.7.2) bookworm; urgency=medium
+
+  * Fix: Go to file failed in big non-git folders such as /root/code: the
+    file walk was cut off at its cap with SIGPIPE, which failed the command
+    and truncated its reply. Producers piped into a cap now tolerate it (also
+    for very large folders and git status). Outside git, Go to file skips
+    build/cache folders and stops at 10,000 files.
+  * Large side-channel replies no longer cost quadratic time in the browser.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Thu, 08 Oct 2026 01:50:50 -0400
+
+devdesk (0.7.1) bookworm; urgency=medium
+
+  * Files pane reworked like VS Code (#37):
+    - Explorer tree beside the editor: folders expand in place (also with
+      the keyboard: arrows, Enter), the open file is highlighted and can be
+      revealed, git colours on names, change dots on folders, gitignored
+      entries dimmed, file-type badges. A drag handle sizes the explorer.
+    - Tabs: a click opens a preview tab (italic) that the next click
+      replaces; double-click or Enter keeps it. Switching tabs is instant and
+      keeps the scroll position. Files Claude changes reload in place.
+    - Go to file (Ctrl+P in the pane, the ⌕ button, the palette): fuzzy
+      search over git ls-files, or a capped find outside git.
+    - Explorer and Changes are two views of the left column; diffs open as
+      tabs.
+    - Expanded folders, open tabs and the active tab are remembered per
+      session; an empty editor offers recent files and the change count.
+    - Narrow panes and phones: the explorer slides over the editor.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Thu, 08 Oct 2026 01:40:47 -0400
+
+devdesk (0.7.0) bookworm; urgency=medium
+
+  * Files pane (#19): a Files button (Ctrl+Shift+E) next to Panels opens the
+    session's folder beside the terminal (a drag-resizable split on wide
+    screens, an overlay on narrow ones and phones).
+    - Browse folders; read files with syntax highlighting (CodeMirror,
+      read-only, Ctrl+F search, line wrap toggle), markdown rendered as a
+      sanitized preview with its relative images, images shown inline.
+    - Changes tab: uncommitted git changes with line counts and a "C" badge
+      on files Claude edited (recorded by the state hook from Edit/Write);
+      diff against HEAD for any changed file. Non-git sessions list the files
+      Claude edited there.
+    - "→ Claude" types @path into the prompt; Copy path.
+    - After Claude's turn the list refreshes, and an open file that changed
+      on disk offers a reload.
+    - Paths stay inside the session folder (no absolute paths, no symlink
+      escapes). Read-only for now; editing is v0.8.0.
+    - The editor (~600 KB) is not in the page: it ships in
+      /usr/share/devdesk/assets, is fetched over ttyd the first time Files
+      opens, checked against the page's SHA-256 and cached in the browser.
+  * Fix: the state hook mis-read hook fields when Claude's message was empty.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Thu, 08 Oct 2026 01:16:26 -0400
+
 devdesk (0.6.1) bookworm; urgency=medium

  * Inbox bell (#36): sessions waiting on you, firing alerts, and what
@@ -35,6 +35,11 @@ Comment: Bundled into index.html at build time:
 2014-2016 SourceLair Private Company, 2012-2013 Christopher Jeffrey);
 JetBrains Mono via @fontsource/jetbrains-mono (OFL-1.1,
 Copyright 2020 The JetBrains Mono Project Authors).
+ Bundled into assets/editor.js (the file viewer) at build time:
+ CodeMirror 6 and @lezer/highlight (MIT, Copyright 2018-2021 Marijn Haverbeke
+ and others); marked (MIT, Copyright 2018+ MarkedJS, 2011-2018 Christopher
+ Jeffrey); DOMPurify (Apache-2.0 or MPL-2.0 at the recipient's choice, here
+ Apache-2.0, Copyright 2025 Dr.-Ing. Mario Heiderich, Cure53).

 License: MIT
 Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -0,0 +1,274 @@
+# shellcheck shell=bash disable=SC2016 # single-quoted jq filters use jq variables
+# File viewer commands (devdesk#19), sourced by bin/devdesk. Every path is
+# relative to the session's folder and must stay inside it: no absolute paths,
+# no newlines, no symlink escapes. Reached through `devdesk attach --fs-*`.
+
+: "${DEVDESK_FS_MAX:=2097152}"        # bytes the viewer opens
+: "${DEVDESK_FS_LIST_MAX:=2000}"      # entries per directory listing
+: "${DEVDESK_ASSETS:=$DEVDESK_SHARE/assets}"
+
+# Producers piped into `head` get SIGPIPE once the cap is reached; under
+# pipefail that would fail the command and cut its reply short, so they are
+# wrapped as `{ producer || true; }`.
+
+# Blob replies: a JSON header line, then base64 between markers (no body for
+# binary files the viewer can't show). The client waits for the END marker.
+DD_BLOB_BEGIN=DEVDESK-BLOB-BEGIN
+DD_BLOB_END=DEVDESK-BLOB-END
+
+dd_session_root() {
+    dd_valid_name "$1" || dd_die "invalid session name: $1"
+    realpath -e -- "$(dd_resolve_dir "$1")" 2>/dev/null || dd_die "the folder of session '$1' is missing"
+}
+
+# dd_fs_path ROOT REL -> the real path of REL inside ROOT, or die.
+dd_fs_path() {
+    local root=$1 rel=${2:-.} p
+    case $rel in
+    /* | *$'\n'* | *$'\r'*) dd_die "bad path: $rel" ;;
+    esac
+    [ -n "$rel" ] || rel=.
+    p=$(realpath -e -- "$root/$rel" 2>/dev/null) || dd_die "no such file: $rel"
+    case "$p/" in
+    "$root"/*) printf '%s\n' "$p" ;;
+    *) dd_die "outside the session folder: $rel" ;;
+    esac
+}
+
+dd_mime() {
+    case ${1,,} in
+    *.png) echo image/png ;;
+    *.jpg | *.jpeg) echo image/jpeg ;;
+    *.gif) echo image/gif ;;
+    *.webp) echo image/webp ;;
+    *.svg) echo image/svg+xml ;;
+    *.ico) echo image/x-icon ;;
+    *.bmp) echo image/bmp ;;
+    *.pdf) echo application/pdf ;;
+    *) echo "" ;;
+    esac
+}
+
+# dd_blob FILE LABEL: header + body for one file on disk.
+dd_blob() {
+    local f=$1 label=$2 size mtime sha mime binary=false utf8=true body=true
+    read -r size mtime < <(stat -c '%s %Y' -- "$f")
+    mime=$(dd_mime "$f")
+    if [ "$size" -gt "$DEVDESK_FS_MAX" ]; then
+        jq -cMn --arg p "$label" --argjson s "$size" --argjson m "$mtime" --argjson max "$DEVDESK_FS_MAX" \
+            '{path: $p, size: $s, mtime: $m, tooLarge: true, max: $max}'
+        return
+    fi
+    if head -c 8192 -- "$f" | grep -qaP '\x00'; then
+        binary=true
+        [ -n "$mime" ] || body=false
+    elif ! iconv -f UTF-8 -t UTF-8 -- "$f" >/dev/null 2>&1; then
+        utf8=false
+    fi
+    sha=$(sha256sum -- "$f" | cut -d' ' -f1)
+    jq -cMn --arg p "$label" --argjson s "$size" --argjson m "$mtime" --arg h "$sha" \
+        --argjson b "$binary" --argjson u "$utf8" --arg mime "$mime" --argjson body "$body" \
+        '{path: $p, size: $s, mtime: $m, sha: $h, binary: $b, utf8: $u, body: $body,
+          mime: (if $mime == "" then null else $mime end)}'
+    printf '%s\n' "$DD_BLOB_BEGIN"
+    if $body; then base64 -w0 -- "$f"; fi
+    printf '\n%s\n' "$DD_BLOB_END"
+}
+
+# --fs-list SESSION [REL]: one directory level, folders first, .git skipped.
+# In a git repository, entries .gitignore covers are flagged (the UI dims them).
+cmd_fs_list() {
+    if [ $# -lt 1 ] || [ $# -gt 2 ]; then dd_die "usage: devdesk attach --fs-list SESSION [PATH]"; fi
+    local root dir rel=${2:-.} tmp ignored=""
+    root=$(dd_session_root "$1")
+    dir=$(dd_fs_path "$root" "$rel")
+    [ -d "$dir" ] || dd_die "not a folder: $rel"
+    tmp=$(mktemp)
+    # %y: type, %Y: type behind a symlink, %s: size, %T@: mtime, %f: name.
+    { find "$dir" -mindepth 1 -maxdepth 1 ! -name .git -printf '%y\t%Y\t%s\t%T@\t%f\0' 2>/dev/null || true; } |
+        head -z -n "$((DEVDESK_FS_LIST_MAX + 1))" >"$tmp"
+    if git --no-optional-locks -C "$dir" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+        ignored=$(tr '\0' '\n' <"$tmp" | cut -f5- | git --no-optional-locks -C "$dir" check-ignore --stdin 2>/dev/null || true)
+    fi
+    jq -cMRs --arg root "$root" --arg rel "${dir#"$root"}" --argjson max "$DEVDESK_FS_LIST_MAX" --arg ign "$ignored" '
+        ($ign | split("\n") | map(select(length > 0) | rtrimstr("/")) | INDEX(.)) as $ignored
+        | (split("\u0000") | map(select(length > 0) | split("\t") |
+            {t: .[0], to: .[1], s: (.[2] | tonumber), m: (.[3] | tonumber | floor), n: (.[4:] | join("\t"))}
+            | if $ignored[.n] then . + {ig: true} else . end)) as $all
+        | {root: $root, dir: ($rel | ltrimstr("/")), truncated: ($all | length > $max),
+           entries: ($all[:$max] | sort_by([(if .t == "d" or .to == "d" then 0 else 1 end), (.n | ascii_downcase)]))}' <"$tmp"
+    rm -f "$tmp"
+}
+
+# --fs-find SESSION: every file under the session folder, for "go to file".
+# git ls-files in a repository (tracked + untracked, .gitignore honoured), else
+# find without node_modules, .git and build/cache folders; capped at
+# DEVDESK_FS_FIND_MAX (10000).
+cmd_fs_find() {
+    [ $# -eq 1 ] || dd_die "usage: devdesk attach --fs-find SESSION"
+    local root max=${DEVDESK_FS_FIND_MAX:-10000}
+    root=$(dd_session_root "$1")
+    if git --no-optional-locks -C "$root" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+        git --no-optional-locks -C "$root" ls-files -co --exclude-standard -z 2>/dev/null || true
+    else
+        (cd "$root" && find . -maxdepth 8 \( -name node_modules -o -name .git -o -name __pycache__ -o -name .venv -o -name venv \
+            -o -name dist -o -name build -o -name target -o -name .cache -o -name .next -o -name coverage \) -prune \
+            -o -type f -printf '%P\0' 2>/dev/null) || true
+    fi | head -z -n "$((max + 1))" |
+        jq -cMRs --argjson max "$max" --arg root "$root" \
+            '(split("\u0000") | map(select(length > 0))) as $f | {root: $root, truncated: ($f | length > $max), files: $f[:$max]}'
+}
+
+# --fs-read SESSION REL
+cmd_fs_read() {
+    [ $# -eq 2 ] || dd_die "usage: devdesk attach --fs-read SESSION PATH"
+    local root f
+    root=$(dd_session_root "$1")
+    f=$(dd_fs_path "$root" "$2")
+    [ -f "$f" ] || dd_die "not a file: $2"
+    dd_blob "$f" "${f#"$root"/}"
+}
+
+# --git-status SESSION: changed files under the session folder, with line counts
+# and whether Claude edited them (from devdesk-state-hook's edit log).
+cmd_git_status() {
+    [ $# -eq 1 ] || dd_die "usage: devdesk attach --git-status SESSION"
+    local root g top prefix branch edits
+    root=$(dd_session_root "$1")
+    edits="$DEVDESK_STATE_DIR/edits/$1.txt"
+    g=(git --no-optional-locks -C "$root")
+    if ! top=$("${g[@]}" rev-parse --show-toplevel 2>/dev/null); then
+        # Not a repository: only what Claude edited.
+        jq -cMn --arg root "$root" --rawfile e <(cat -- "$edits" 2>/dev/null || true) '
+            {git: false, root: $root, files: [$e | split("\n")[] | select(length > 0) | select(startswith($root + "/"))
+                | {path: ltrimstr($root + "/"), x: " ", y: " ", claude: true}]}'
+        return
+    fi
+    prefix=$("${g[@]}" rev-parse --show-prefix)
+    branch=$("${g[@]}" symbolic-ref --short -q HEAD || echo "(detached)")
+    {
+        printf 'S\n'
+        { "${g[@]}" status --porcelain=v1 -z --untracked-files=all -- . 2>/dev/null || true; } | head -z -n 1000 | tr '\0' '\n'
+        printf 'N\n'
+        { "${g[@]}" diff --numstat HEAD -- . 2>/dev/null || true; } | head -n 1000
+    } | jq -cMRs --arg root "$root" --arg top "$top" --arg prefix "$prefix" --arg branch "$branch" \
+        --rawfile e <(cat -- "$edits" 2>/dev/null || true) '
+        (split("\nN\n") | .[0] | ltrimstr("S\n") | split("\n") | map(select(length > 2))) as $st
+        | (split("\nN\n") | .[1] // "" | split("\n") | map(select(length > 0) | split("\t")
+            | {key: .[2:] | join("\t"), value: {add: (.[0] | tonumber? // null), del: (.[1] | tonumber? // null)}}) | from_entries) as $num
+        | ($e | split("\n") | map(select(length > 0))) as $claude
+        # porcelain -z: "XY path", and after a rename/copy entry the next item is the old path.
+        | reduce range(0; $st | length) as $i ({skip: false, files: []};
+            if .skip then .skip = false
+            else ($st[$i]) as $line | ($line[3:]) as $p
+              | .files += [{repoPath: $p, x: $line[0:1], y: $line[1:2],
+                            from: (if ($line[0:1] | test("[RC]")) then $st[$i + 1] else null end)}]
+              | .skip = ($line[0:1] | test("[RC]"))
+            end)
+        | .files | map(. + {path: (if (.repoPath | startswith($prefix)) then .repoPath | ltrimstr($prefix) else null end),
+                            add: $num[.repoPath].add, del: $num[.repoPath].del,
+                            claude: (($top + "/" + .repoPath) as $abs | any($claude[]; . == $abs))}) as $files
+        | {git: true, root: $root, branch: $branch,
+           files: ($files + [$claude[] | select(startswith($root + "/")) | ltrimstr($root + "/") as $p
+                     | select(any($files[]; .path == $p) | not)
+                     | {path: $p, repoPath: null, x: " ", y: " ", claude: true}])}'
+}
+
+# --git-show SESSION REL: the HEAD version of a file, for diffs. An empty body
+# when HEAD doesn't have it (new file).
+cmd_git_show() {
+    [ $# -eq 2 ] || dd_die "usage: devdesk attach --git-show SESSION PATH"
+    local root g top prefix tmp rel=$2
+    root=$(dd_session_root "$1")
+    case $rel in /* | *$'\n'* | *..*) dd_die "bad path: $rel" ;; esac
+    g=(git --no-optional-locks -C "$root")
+    top=$("${g[@]}" rev-parse --show-toplevel 2>/dev/null) || dd_die "not a git repository"
+    prefix=$("${g[@]}" rev-parse --show-prefix)
+    tmp=$(mktemp)
+    "${g[@]}" show "HEAD:$prefix$rel" >"$tmp" 2>/dev/null || : >"$tmp"
+    dd_blob "$tmp" "$rel"
+    rm -f "$tmp"
+}
+
+# --fs-write SESSION REL BYTES BASE (devdesk#20): save a file from the editor.
+# The content arrives as base64 on stdin after the READY line (like uploads).
+# BASE is the sha256 the editor loaded: if the file changed since, nothing is
+# written and the reply is {conflict: true, sha: <current>}. BASE "new" creates
+# a file (and missing folders) and refuses to overwrite one. Writes go to a
+# temp file in the same folder, keep the mode and owner, and land with mv.
+cmd_fs_write() {
+    [ $# -eq 4 ] || dd_die "usage: devdesk attach --fs-write SESSION PATH BYTES BASESHA|new"
+    local root rel=$2 size=$3 base=$4 target dir name tmp b64len actual current sha mtime
+    root=$(dd_session_root "$1")
+    if ! [[ $size =~ ^[0-9]+$ ]] || [ "$size" -gt "$DEVDESK_FS_MAX" ]; then
+        dd_die "too large: the editor saves files up to $((DEVDESK_FS_MAX / 1024)) KiB"
+    fi
+    [[ $base =~ ^([0-9a-f]{64}|new)$ ]] || dd_die "bad base: $base"
+    case $rel in /* | *$'\n'* | *$'\r'* | '' | */ | . | ..) dd_die "bad path: $rel" ;; esac
+    name=${rel##*/}
+    if [ "$name" = . ] || [ "$name" = .. ]; then dd_die "bad path: $rel"; fi
+    if [ "$base" = new ]; then
+        if [ -e "$root/$rel" ] || [ -L "$root/$rel" ]; then dd_die "already exists: $rel"; fi
+        case $rel in */*) dir=$root/${rel%/*} ;; *) dir=$root ;; esac
+        # Missing folders are created, but never through a symlink out of the
+        # root: check the deepest folder that exists before creating any.
+        local existing=$dir
+        while [ ! -e "$existing" ]; do existing=${existing%/*}; done
+        existing=${existing#"$root"}
+        dd_fs_path "$root" "${existing#/}" >/dev/null
+        mkdir -p -- "$dir" || dd_die "cannot create folder for $rel"
+        dir=${dir#"$root"}
+        dir=$(dd_fs_path "$root" "${dir#/}")
+        target="$dir/$name"
+    else
+        target=$(dd_fs_path "$root" "$rel")
+        [ -f "$target" ] || dd_die "not a file: $rel"
+        dir=${target%/*}
+    fi
+    tmp=$(mktemp --tmpdir="$dir" ".${name}.devdesk-XXXXXX") || dd_die "cannot write in ${dir#"$root"/}"
+    trap 'rm -f "$tmp"' HUP INT TERM
+    # shellcheck disable=SC2017 # integer ceil(size/3)*4: the base64 length, on purpose
+    b64len=$(((size + 2) / 3 * 4))
+    stty raw -echo 2>/dev/null || true
+    printf 'DEVDESK-WRITE-READY\r\n'
+    if [ "$b64len" -gt 0 ]; then
+        head -c "$b64len" | base64 -d >"$tmp" 2>/dev/null || true
+    fi
+    stty sane 2>/dev/null || true
+    actual=$(stat -c %s "$tmp" 2>/dev/null || echo 0)
+    if [ "$actual" != "$size" ]; then
+        rm -f "$tmp"
+        dd_die "save incomplete ($actual of $size bytes)"
+    fi
+    if [ "$base" = new ]; then
+        if [ -e "$target" ]; then
+            rm -f "$tmp"
+            dd_die "already exists: $rel"
+        fi
+        chmod 0644 "$tmp"
+    else
+        current=$(sha256sum -- "$target" | cut -d' ' -f1)
+        if [ "$current" != "$base" ]; then
+            rm -f "$tmp"
+            trap - HUP INT TERM
+            jq -cMn --arg p "$rel" --arg h "$current" '{ok: false, conflict: true, path: $p, sha: $h}'
+            return
+        fi
+        chmod --reference="$target" "$tmp" 2>/dev/null || true
+        chown --reference="$target" "$tmp" 2>/dev/null || true
+    fi
+    mv -f -- "$tmp" "$target" || { rm -f "$tmp"; dd_die "cannot replace $rel"; }
+    trap - HUP INT TERM
+    sha=$(sha256sum -- "$target" | cut -d' ' -f1)
+    mtime=$(stat -c %Y -- "$target")
+    jq -cMn --arg p "${target#"$root"/}" --arg h "$sha" --argjson s "$size" --argjson m "$mtime" \
+        '{ok: true, path: $p, sha: $h, size: $s, mtime: $m}'
+}
+
+# --asset NAME: a lazily loaded part of the web UI (the file viewer's editor),
+# shipped in $DEVDESK_ASSETS and cached by the browser.
+cmd_asset() {
+    if [ $# -ne 1 ] || ! [[ $1 =~ ^[a-z0-9-]+\.js$ ]]; then dd_die "usage: devdesk attach --asset NAME.js"; fi
+    [ -f "$DEVDESK_ASSETS/$1" ] || dd_die "no such asset: $1"
+    dd_blob "$DEVDESK_ASSETS/$1" "$1"
+}
@@ -132,7 +132,7 @@ dd_registry_set_claude() {

 dd_registry_remove() {
    dd_registry_update 'del(.sessions[$n])' --arg n "$1"
-    rm -f "$DEVDESK_CONTEXT_DIR/$1.json" "$DEVDESK_STATUS_DIR/$1.json"
+    rm -f "$DEVDESK_CONTEXT_DIR/$1.json" "$DEVDESK_STATUS_DIR/$1.json" "$DEVDESK_STATE_DIR/edits/$1.txt"
 }

 dd_registry_rename() {
@@ -144,6 +144,9 @@ dd_registry_rename() {
            mv -f "$d/$1.json" "$d/$2.json"
        fi
    done
+    if [ -f "$DEVDESK_STATE_DIR/edits/$1.txt" ]; then
+        mv -f "$DEVDESK_STATE_DIR/edits/$1.txt" "$DEVDESK_STATE_DIR/edits/$2.txt"
+    fi
 }

 # Project name (directory or its slug) -> absolute directory inside the projects root.
@@ -28,7 +28,9 @@ attached=$(dd_tmux list-sessions -F '#{session_name} #{session_attached}' 2>/dev

 message=$(jq -rM '.message // "Claude is waiting for your input"' "$state_file" 2>/dev/null)
 url=""
-[ -z "$DEVDESK_PUBLIC_URL" ] || url="${DEVDESK_PUBLIC_URL%/}/?arg=$session"
+# existing=1: if the session was ended by the time you tap, say so instead of
+# starting a new Claude there (devdesk#38).
+[ -z "$DEVDESK_PUBLIC_URL" ] || url="${DEVDESK_PUBLIC_URL%/}/?arg=$session&existing=1"
 body=$(jq -cMn --arg s "$session" --arg m "$message" --arg u "$url" --arg h "$(hostname)" \
    '{session: $s, message: $m, url: (if $u == "" then null else $u end), host: $h,
      text: ("Claude needs you in " + $s + ": " + $m + (if $u == "" then "" else " — " + $u end))}')
@@ -16,7 +16,23 @@ outer=${TMUX:-}
 session=$(tmux display-message -p -t "$TMUX_PANE" '#S' 2>/dev/null)
 [[ $session =~ ^[A-Za-z0-9][A-Za-z0-9_-]{0,63}$ ]] || exit 0

-IFS=$'\t' read -r event message < <(jq -rM '[.hook_event_name // "", (.message // "" | gsub("[\t\n]"; " "))] | @tsv' <<<"$input" 2>/dev/null)
+# Unit separator, not tab: read collapses runs of whitespace delimiters, so an
+# empty field would shift the ones after it.
+IFS=$'\x1f' read -r event message tool file < <(jq -rM '[.hook_event_name // "", (.message // "" | gsub("[\u001f\n]"; " ")),
+    .tool_name // "", (.tool_input.file_path // .tool_input.notebook_path // "" | gsub("[\u001f\n]"; " "))] | join("\u001f")' <<<"$input" 2>/dev/null)
+
+# Files Claude edits, for the file viewer's "Claude" badge (devdesk#19).
+case $event:$tool in
+PostToolUse:Edit | PostToolUse:Write | PostToolUse:MultiEdit | PostToolUse:NotebookEdit)
+    if [[ $file == /* ]]; then
+        log="${DEVDESK_STATE_DIR:-/var/lib/devdesk}/edits/$session.txt"
+        mkdir -p "${log%/*}" 2>/dev/null
+        if ! grep -qxF -- "$file" "$log" 2>/dev/null && [ "$(wc -l <"$log" 2>/dev/null || echo 0)" -lt 1000 ]; then
+            printf '%s\n' "$file" >>"$log"
+        fi
+    fi
+    ;;
+esac
 case $event in
 UserPromptSubmit | PostToolUse) state=working ;;
 Notification) state=waiting ;;
@@ -7,20 +7,215 @@
      "name": "devdesk",
      "license": "MIT",
      "devDependencies": {
+        "@codemirror/commands": "6.11.1",
+        "@codemirror/lang-markdown": "6.5.2",
+        "@codemirror/language": "6.13.1",
+        "@codemirror/legacy-modes": "6.5.5",
+        "@codemirror/merge": "6.12.2",
+        "@codemirror/search": "6.7.2",
+        "@codemirror/state": "6.7.6",
+        "@codemirror/view": "6.43.14",
        "@fontsource/jetbrains-mono": "5.3.0",
+        "@lezer/highlight": "1.2.5",
        "@xterm/addon-clipboard": "0.2.0",
        "@xterm/addon-fit": "0.11.0",
        "@xterm/addon-unicode11": "0.9.0",
        "@xterm/addon-web-links": "0.12.0",
        "@xterm/addon-webgl": "0.19.0",
        "@xterm/xterm": "6.0.0",
+        "dompurify": "3.4.16",
        "esbuild": "0.28.2",
-        "eslint": "8.57.1"
+        "eslint": "8.57.1",
+        "marked": "18.1.0"
      },
      "engines": {
        "node": ">=18"
      }
    },
+    "node_modules/@codemirror/autocomplete": {
+      "version": "6.20.3",
+      "resolved": "https://registry.npmjs.org/@codemirror/autocomplete/-/autocomplete-6.20.3.tgz",
+      "integrity": "sha512-tlosUqb+3BbxCxZdu4tKeRghPFC+QM7q4X5YhKV2eCmPG+1r2F3f4AaSz5sCrFqUtX4Jh20VFTKecl16MgiV9g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/commands": {
+      "version": "6.11.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/commands/-/commands-6.11.1.tgz",
+      "integrity": "sha512-O/4hG3SC1YwcmQ0d2UVNDs+AsaNWd1iHVxbTeEBuqH+6bExAiPK3iS/BvpY6rZGURALv4ZD3sIgcCmRvw3ehBg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.7.0",
+        "@codemirror/view": "^6.27.0",
+        "@lezer/common": "^1.1.0"
+      }
+    },
+    "node_modules/@codemirror/lang-css": {
+      "version": "6.3.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-css/-/lang-css-6.3.1.tgz",
+      "integrity": "sha512-kr5fwBGiGtmz6l0LSJIbno9QrifNMUusivHbnA1H6Dmqy4HZFte3UAICix1VuKo0lMPKQr2rqB+0BkKi/S3Ejg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@lezer/common": "^1.0.2",
+        "@lezer/css": "^1.1.7"
+      }
+    },
+    "node_modules/@codemirror/lang-html": {
+      "version": "6.4.12",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-html/-/lang-html-6.4.12.tgz",
+      "integrity": "sha512-pw2ReWKUqSkbvh76RAT4NYxiogRu+PWkR2ukAwO9uOgrm8uipkzjtKKtNpyeAQwHOqxEeSvAXZ6vr3AfyB9y/w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/lang-css": "^6.0.0",
+        "@codemirror/lang-javascript": "^6.0.0",
+        "@codemirror/language": "^6.4.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/css": "^1.1.0",
+        "@lezer/html": "^1.3.12"
+      }
+    },
+    "node_modules/@codemirror/lang-javascript": {
+      "version": "6.2.5",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-javascript/-/lang-javascript-6.2.5.tgz",
+      "integrity": "sha512-zD4e5mS+50htS7F+TYjBPsiIFGanfVqg4HyUz6WNFikgOPf2BgKlx+TQedI1w6n/IqRBVBbBWmGFdLB/7uxO4A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.6.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/javascript": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-markdown": {
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-markdown/-/lang-markdown-6.5.2.tgz",
+      "integrity": "sha512-AwBOdkWYuA//WcM0xO5PfHPUcmz/O2i5o0Nsg1U69SII/loCJlFI1Romd9xp2HYb1kYJRGZotyqRghuHH5n8Kw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.7.1",
+        "@codemirror/lang-html": "^6.0.0",
+        "@codemirror/language": "^6.3.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.2.1",
+        "@lezer/markdown": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/language": {
+      "version": "6.13.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/language/-/language-6.13.1.tgz",
+      "integrity": "sha512-zfvU2r3TyylQLMj/te+5CnQ0rSqZi8B1oTCBbQkagcLW4Xc6imab6qN+pEJhsuNOLaJqiRyBXp9UhWA1DhVvDw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/streamparser": "^6.0.0",
+        "@codemirror/view": "^6.23.0",
+        "@lezer/common": "^1.5.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0",
+        "style-mod": "^4.0.0"
+      }
+    },
+    "node_modules/@codemirror/legacy-modes": {
+      "version": "6.5.5",
+      "resolved": "https://registry.npmjs.org/@codemirror/legacy-modes/-/legacy-modes-6.5.5.tgz",
+      "integrity": "sha512-9ltT214oMb3Y1w5eAZMSigzrjzZnMI2Wa3Feq73rU/i4C56MkwrpfswfQYOr28C5pXr6dWwspNTMyeHXlzWMxg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/streamparser": "^6.0.0"
+      }
+    },
+    "node_modules/@codemirror/lint": {
+      "version": "6.9.7",
+      "resolved": "https://registry.npmjs.org/@codemirror/lint/-/lint-6.9.7.tgz",
+      "integrity": "sha512-28/+iWLYxKxsvGYhSYL7zaCZqLz5+FFFDq9tVsvGv9kv8RY4fFAchJ5WX9M3YrrRlTIsECjsXPqeNgnSmNP2dg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.42.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/merge": {
+      "version": "6.12.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/merge/-/merge-6.12.2.tgz",
+      "integrity": "sha512-V8JvyAPjHbPupqP7BeMcsdsYCbyPij74jxIbaIJDORI+VZzW44zFmon8bF+oxGWvOKhcRmkiUMXd8MxHr3YA2w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.17.0",
+        "@lezer/highlight": "^1.0.0",
+        "style-mod": "^4.1.0"
+      }
+    },
+    "node_modules/@codemirror/search": {
+      "version": "6.7.2",
+      "resolved": "https://registry.npmjs.org/@codemirror/search/-/search-6.7.2.tgz",
+      "integrity": "sha512-gUYkYhT2+n/+VGZ+8EzE5WFkYZUZYm1VOKDudIsNqh42uRVQJ0a6Yss9sdKT3MeOYfuL1N6AZA57oza0Oyr0LA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.37.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/state": {
+      "version": "6.7.6",
+      "resolved": "https://registry.npmjs.org/@codemirror/state/-/state-6.7.6.tgz",
+      "integrity": "sha512-kAz+AncRtKuIknedxT1bq4XwXv4UowhbkHU1myPrtVb/jZtImWuV5BXzv5vK6i3kYACsdiZiQKFQQ5Mq7elW8w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@marijn/find-cluster-break": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/streamparser": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/streamparser/-/streamparser-6.0.0.tgz",
+      "integrity": "sha512-JTFPF6xrfjt0mnfGPgzcLiMwYmvIyNaoizp8BYzv8FE8KrT6GBGDZ190rtt+O7Wke3gG/MFHyiY9YGNeimof4w==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@codemirror/view": {
+      "version": "6.43.14",
+      "resolved": "https://registry.npmjs.org/@codemirror/view/-/view-6.43.14.tgz",
+      "integrity": "sha512-hC45YnmJNR1rz42OF57BLoQNFMV12/13drnvibDsR2quNDmldcb4WvYVV81hFQg56i9lcqQMEDqilhX2QDcGQQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@codemirror/state": "^6.7.0",
+        "crelt": "^1.0.6",
+        "style-mod": "^4.1.0",
+        "w3c-keyname": "^2.2.4"
+      }
+    },
    "node_modules/@esbuild/aix-ppc64": {
      "version": "0.28.2",
      "resolved": "https://registry.npmjs.org/@esbuild/aix-ppc64/-/aix-ppc64-0.28.2.tgz",
@@ -574,6 +769,87 @@
      "dev": true,
      "license": "BSD-3-Clause"
    },
+    "node_modules/@lezer/common": {
+      "version": "1.5.3",
+      "resolved": "https://registry.npmjs.org/@lezer/common/-/common-1.5.3.tgz",
+      "integrity": "sha512-H0iErY4e43LpXbYDyBci5W4v/RwTgGV3YzYOlJPiGZ8RY8w51kVE+xLn1tg3Z6UmSfyETvtsUK3r7YsgDQEI7Q==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@lezer/css": {
+      "version": "1.3.9",
+      "resolved": "https://registry.npmjs.org/@lezer/css/-/css-1.3.9.tgz",
+      "integrity": "sha512-ZmzgvTOBdJWGIsY/ItAfN7UW8DV802oZG+jeG6E508SwEzz5YhuAajptpWPICvIyqYAD2+VjMdOS40GgGkyEOQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/highlight": {
+      "version": "1.2.5",
+      "resolved": "https://registry.npmjs.org/@lezer/highlight/-/highlight-1.2.5.tgz",
+      "integrity": "sha512-O1GMVKgtf5YspFaRzpmqkVgMtIk2HG9uMAbH6wdAIdNh3TVzCsch/+cRi+6l2//UGDKe6NB9BW3cvuR5ezMQ0w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/html": {
+      "version": "1.3.13",
+      "resolved": "https://registry.npmjs.org/@lezer/html/-/html-1.3.13.tgz",
+      "integrity": "sha512-oI7n6NJml729m7pjm9lvLvmXbdoMoi2f+1pwSDJkl9d68zGr7a9Btz8NdHTGQZtW2DA25ybeuv/SyDb9D5tseg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/javascript": {
+      "version": "1.5.6",
+      "resolved": "https://registry.npmjs.org/@lezer/javascript/-/javascript-1.5.6.tgz",
+      "integrity": "sha512-sEvOqpl4vJQca0NugSQK02vQPbc5KrvoojnYGoqqFgFO0MtcYhwGiHKVEB+LuXYJnfyXo4QPA8ztbrEa4Fw5NA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.2.0",
+        "@lezer/highlight": "^1.1.3",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/lr": {
+      "version": "1.4.11",
+      "resolved": "https://registry.npmjs.org/@lezer/lr/-/lr-1.4.11.tgz",
+      "integrity": "sha512-UwgZcl1R66H2hDzBrA7kWyYmX6s8p5TQ+e/t7CuvgCtBEPxbEPaHYHu+pJBvTvDotEJpuQkJjbXuHiw5Cixxgw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/markdown": {
+      "version": "1.8.0",
+      "resolved": "https://registry.npmjs.org/@lezer/markdown/-/markdown-1.8.0.tgz",
+      "integrity": "sha512-X6w3A2NpyhdtGqTWRJB8gR4QDXBaFMbTOs780ZdZ15KKCfBXOQTKcB3Vr+W6tqJHVlealt53tLmHRvOqPTQgYA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lezer/common": "^1.5.0",
+        "@lezer/highlight": "^1.0.0"
+      }
+    },
+    "node_modules/@marijn/find-cluster-break": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/@marijn/find-cluster-break/-/find-cluster-break-1.0.4.tgz",
+      "integrity": "sha512-Wy0V7+SGUjnF9/TkiM1hKVDPj7jKXduPNboMVtHTA8dySMURWqfg/JZ9E2Sq8JgSJmkl7k7Qe9FLeMSrSraWmQ==",
+      "dev": true,
+      "license": "MIT"
+    },
    "node_modules/@nodelib/fs.scandir": {
      "version": "2.1.5",
      "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -612,6 +888,14 @@
        "node": ">= 8"
      }
    },
+    "node_modules/@types/trusted-types": {
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true
+    },
    "node_modules/@ungap/structured-clone": {
      "version": "1.4.0",
      "resolved": "https://registry.npmjs.org/@ungap/structured-clone/-/structured-clone-1.4.0.tgz",
@@ -812,6 +1096,13 @@
      "dev": true,
      "license": "MIT"
    },
+    "node_modules/crelt": {
+      "version": "1.0.7",
+      "resolved": "https://registry.npmjs.org/crelt/-/crelt-1.0.7.tgz",
+      "integrity": "sha512-aK6BbWfhf4U/wCcLHKPJl/xa6VkVstRaPywWtMKGwuOLc/wZTyQYuoxgvZnNsBvv7Kg3YTBQYYBCggcviQczuA==",
+      "dev": true,
+      "license": "MIT"
+    },
    "node_modules/cross-spawn": {
      "version": "7.0.6",
      "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
@@ -865,6 +1156,16 @@
        "node": ">=6.0.0"
      }
    },
+    "node_modules/dompurify": {
+      "version": "3.4.16",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.4.16.tgz",
+      "integrity": "sha512-sqo+pNp3qRhCIpbgRi1y8Tgk27Bo2Ry7w0dC1NBeNTdZChWjz9Xb/KOoZbRP/R6pQZ80Qw8YhXw13hWWBbMRnQ==",
+      "dev": true,
+      "license": "(MPL-2.0 OR Apache-2.0)",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
    "node_modules/esbuild": {
      "version": "0.28.2",
      "resolved": "https://registry.npmjs.org/esbuild/-/esbuild-0.28.2.tgz",
@@ -1423,6 +1724,19 @@
      "dev": true,
      "license": "MIT"
    },
+    "node_modules/marked": {
+      "version": "18.1.0",
+      "resolved": "https://registry.npmjs.org/marked/-/marked-18.1.0.tgz",
+      "integrity": "sha512-PamYXWWWg2nboG3oX5Ffzpy3EFZROqZJK9hSlMmUnekp7TxPs5DcT95vwd46m73/exfKCRVMtgXoPMI4FEJL6w==",
+      "dev": true,
+      "license": "MIT",
+      "bin": {
+        "marked": "bin/marked.js"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
    "node_modules/minimatch": {
      "version": "3.1.5",
      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.5.tgz",
@@ -1705,6 +2019,13 @@
        "url": "https://github.com/sponsors/sindresorhus"
      }
    },
+    "node_modules/style-mod": {
+      "version": "4.1.4",
+      "resolved": "https://registry.npmjs.org/style-mod/-/style-mod-4.1.4.tgz",
+      "integrity": "sha512-XXWIQt633/EpAFx8aZDOTjBzrCaGmhvEQlQo6MVPfa2OzO2cWo+4hV9h+6UkHYlXGfy+ODXKUdP7Pthmcu5ATw==",
+      "dev": true,
+      "license": "MIT"
+    },
    "node_modules/supports-color": {
      "version": "7.2.0",
      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-7.2.0.tgz",
@@ -1761,6 +2082,13 @@
        "punycode": "^2.1.0"
      }
    },
+    "node_modules/w3c-keyname": {
+      "version": "2.2.8",
+      "resolved": "https://registry.npmjs.org/w3c-keyname/-/w3c-keyname-2.2.8.tgz",
+      "integrity": "sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==",
+      "dev": true,
+      "license": "MIT"
+    },
    "node_modules/which": {
      "version": "2.0.2",
      "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
@@ -4,21 +4,34 @@
  "description": "Persistent browser terminal for Claude Code (ttyd + tmux), LotusGuild TDS styling",
  "license": "MIT",
  "type": "module",
-  "engines": { "node": ">=18" },
+  "engines": {
+    "node": ">=18"
+  },
  "scripts": {
    "build": "node web/build.mjs",
-    "lint": "eslint --ext .js,.mjs web/src web/build.mjs tests/protocol.test.mjs",
+    "lint": "eslint --ext .js,.mjs web/src web/editor web/build.mjs tests/protocol.test.mjs",
    "test": "node --test tests/*.test.mjs"
  },
  "devDependencies": {
+    "@codemirror/commands": "6.11.1",
+    "@codemirror/lang-markdown": "6.5.2",
+    "@codemirror/language": "6.13.1",
+    "@codemirror/legacy-modes": "6.5.5",
+    "@codemirror/merge": "6.12.2",
+    "@codemirror/search": "6.7.2",
+    "@codemirror/state": "6.7.6",
+    "@codemirror/view": "6.43.14",
    "@fontsource/jetbrains-mono": "5.3.0",
+    "@lezer/highlight": "1.2.5",
    "@xterm/addon-clipboard": "0.2.0",
    "@xterm/addon-fit": "0.11.0",
    "@xterm/addon-unicode11": "0.9.0",
    "@xterm/addon-web-links": "0.12.0",
    "@xterm/addon-webgl": "0.19.0",
    "@xterm/xterm": "6.0.0",
+    "dompurify": "3.4.16",
    "esbuild": "0.28.2",
-    "eslint": "8.57.1"
+    "eslint": "8.57.1",
+    "marked": "18.1.0"
  }
 }
@@ -310,7 +310,7 @@ posts() { [ -f "$TMP/posts" ] && wc -l <"$TMP/posts" || echo 0; }
    sleep 2.5
    [ "$(posts)" -eq 1 ]
    run jq -r '[.session, .url, (.text | test("Claude needs you in alpha"))] | @tsv' "$TMP/posts"
-    [ "$output" = "$(printf 'alpha\thttps://dev.example.org/?arg=alpha\ttrue')" ]
+    [ "$output" = "$(printf 'alpha\thttps://dev.example.org/?arg=alpha&existing=1\ttrue')" ]

    # answered within the delay: nothing is posted
    echo '{"hook_event_name":"PostToolUse"}' | hook
@@ -491,3 +491,187 @@ posts() { [ -f "$TMP/posts" ] && wc -l <"$TMP/posts" || echo 0; }
    run claude_args alpha
    [ "$output" = "-n alpha --settings $REPO/share/claude-settings.json --remote-control devdesk-alpha" ]
 }
+
+# Decode a blob reply (header line, base64 between markers) into $TMP/blob.
+blob_body() {
+    sed -n '/^DEVDESK-BLOB-BEGIN$/,/^DEVDESK-BLOB-END$/p' <<<"$1" | sed '1d;$d' | base64 -d >"$TMP/blob"
+}
+
+@test "fs-list lists one level, folders first, and stays inside the session folder (#19)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    mkdir -p "$p/src/deep" "$p/.git"
+    echo hi >"$p/README.md"
+    echo x >"$p/src/a.sh"
+    ln -s "$TMP/outside" "$p/escape-link"
+    ln -s src "$p/src-link"
+    run devdesk attach --fs-list alpha
+    [ "$status" -eq 0 ]
+    # Folders first (a symlink to a folder counts, even one that escapes: opening it fails).
+    [ "$(jq -r '[.entries[].n] | join(",")' <<<"$output")" = "escape-link,src,src-link,README.md" ]
+    run devdesk attach --fs-list alpha src
+    [ "$(jq -r '.dir + ":" + ([.entries[].n] | join(","))' <<<"$output")" = "src:deep,a.sh" ]
+    for bad in ../ /etc escape-link "src/../../alpha/../../outside"; do
+        run devdesk attach --fs-list alpha "$bad"
+        [ "$status" -ne 0 ]
+    done
+    run devdesk attach --fs-list alpha src-link
+    [ "$status" -eq 0 ]
+}
+
+@test "fs-read returns text, images and refuses binaries, big files and escapes (#19)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    printf 'line 1\r\nüñí\n' >"$p/notes.md"
+    printf '\x89PNG\r\n\x1a\n\0\0\0' >"$p/pic.png"
+    head -c 100 /dev/zero >"$p/blob.bin"
+    head -c 3000 /dev/zero | tr '\0' a >"$p/big.txt"
+    run devdesk attach --fs-read alpha notes.md
+    [ "$status" -eq 0 ]
+    [ "$(head -n1 <<<"$output" | jq -r '[.path, .binary, .utf8, .body] | @tsv')" = "$(printf 'notes.md\tfalse\ttrue\ttrue')" ]
+    blob_body "$output"
+    cmp "$TMP/blob" "$p/notes.md"
+    run devdesk attach --fs-read alpha pic.png
+    [ "$(head -n1 <<<"$output" | jq -r '[.mime, .body] | @tsv')" = "$(printf 'image/png\ttrue')" ]
+    run devdesk attach --fs-read alpha blob.bin
+    [ "$(head -n1 <<<"$output" | jq -r '[.binary, .body] | @tsv')" = "$(printf 'true\tfalse')" ]
+    run env DEVDESK_FS_MAX=1000 "$REPO/bin/devdesk" attach --fs-read alpha big.txt
+    [ "$(head -n1 <<<"$output" | jq -r '.tooLarge')" = true ]
+    run devdesk attach --fs-read alpha ../alpha/../../outside
+    [ "$status" -ne 0 ]
+}
+
+@test "git-status and git-show report changes, line counts and Claude's edits (#19)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    git -C "$p" init -q -b main
+    git -C "$p" -c user.name=t -c user.email=t@t commit -q --allow-empty -m init
+    printf 'one\ntwo\n' >"$p/kept.txt"
+    printf 'old\n' >"$p/moved.txt"
+    git -C "$p" add . && git -C "$p" -c user.name=t -c user.email=t@t commit -q -m files
+    printf 'one\nTWO\nthree\n' >"$p/kept.txt"
+    git -C "$p" mv moved.txt renamed.txt
+    echo new >"$p/fresh.txt"
+    mkdir -p "$DEVDESK_STATE_DIR/edits"
+    printf '%s\n' "$p/kept.txt" "$p/notes-outside-git.txt" >"$DEVDESK_STATE_DIR/edits/alpha.txt"
+    run devdesk attach --git-status alpha
+    [ "$status" -eq 0 ]
+    [ "$(jq -r '.files | map("\(.x)\(.y) \(.path) +\(.add) -\(.del) \(.claude)") | sort | join("|")' <<<"$output")" = \
+        "   notes-outside-git.txt +null -null true| M kept.txt +2 -1 true|?? fresh.txt +null -null false|R  renamed.txt +null -null false" ]
+    [ "$(jq -r '.files[] | select(.path == "renamed.txt") | .from' <<<"$output")" = moved.txt ]
+    run devdesk attach --git-show alpha kept.txt
+    blob_body "$output"
+    [ "$(cat "$TMP/blob")" = "$(printf 'one\ntwo')" ]
+    run devdesk attach --git-show alpha fresh.txt
+    [ "$(head -n1 <<<"$output" | jq -r '.size')" = 0 ]
+    run devdesk attach --git-status alpha
+    run env DEVDESK_PROJECTS_ROOT="$TMP/outside" "$REPO/bin/devdesk" attach --git-status alpha
+    [ "$status" -eq 0 ]
+}
+
+@test "the state hook logs Claude's edits; rename moves and end removes the log (#19)" {
+    start_server
+    devdesk new alpha
+    pane=$(tmux -S "$DEVDESK_SOCKET" display -p -t =alpha:shell '#{pane_id}')
+    hook() { TMUX="$DEVDESK_SOCKET,1,0" TMUX_PANE="$pane" "$REPO/libexec/devdesk-state-hook"; }
+    echo '{"hook_event_name":"PostToolUse","tool_name":"Edit","tool_input":{"file_path":"/x/a.txt"}}' | hook
+    echo '{"hook_event_name":"PostToolUse","tool_name":"Write","tool_input":{"file_path":"/x/a.txt"}}' | hook
+    echo '{"hook_event_name":"PostToolUse","tool_name":"Bash","tool_input":{"command":"ls"}}' | hook
+    echo '{"hook_event_name":"PostToolUse","tool_name":"NotebookEdit","tool_input":{"notebook_path":"/x/n.ipynb"}}' | hook
+    [ "$(cat "$DEVDESK_STATE_DIR/edits/alpha.txt")" = "$(printf '/x/a.txt\n/x/n.ipynb')" ]
+    devdesk rename alpha beta
+    [ -f "$DEVDESK_STATE_DIR/edits/beta.txt" ] && [ ! -e "$DEVDESK_STATE_DIR/edits/alpha.txt" ]
+    devdesk end beta
+    [ ! -e "$DEVDESK_STATE_DIR/edits/beta.txt" ]
+}
+
+@test "asset serves only named .js files from the assets folder (#19)" {
+    mkdir -p "$TMP/assets"
+    echo 'window.X = 1;' >"$TMP/assets/editor.js"
+    run env DEVDESK_ASSETS="$TMP/assets" "$REPO/bin/devdesk" attach --asset editor.js
+    [ "$status" -eq 0 ]
+    blob_body "$output"
+    cmp "$TMP/blob" "$TMP/assets/editor.js"
+    for bad in ../etc/passwd editor.css nope.js; do
+        run env DEVDESK_ASSETS="$TMP/assets" "$REPO/bin/devdesk" attach --asset "$bad"
+        [ "$status" -ne 0 ]
+    done
+}
+
+@test "fs-list flags gitignored entries; fs-find lists files for go-to-file (#37)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    git -C "$p" init -q -b main
+    mkdir -p "$p/src" "$p/build" "$p/node_modules/x"
+    printf 'build/\n*.log\n' >"$p/.gitignore"
+    echo a >"$p/src/a.js"
+    echo b >"$p/debug.log"
+    echo c >"$p/node_modules/x/i.js"
+    run devdesk attach --fs-list alpha
+    [ "$(jq -r '[.entries[] | select(.ig) | .n] | join(",")' <<<"$output")" = "build,debug.log" ]
+    run devdesk attach --fs-find alpha
+    [ "$(jq -r '.files | sort | join(",")' <<<"$output")" = ".gitignore,node_modules/x/i.js,src/a.js" ]
+    # Outside git: find, without node_modules
+    rm -rf "$p/.git"
+    run devdesk attach --fs-find alpha
+    [ "$(jq -r '.files | sort | join(",")' <<<"$output")" = ".gitignore,debug.log,src/a.js" ]
+    # Hitting the cap must not fail the command (SIGPIPE in the producer).
+    for i in $(seq 1 3000); do : >"$p/src/f$i.txt"; done
+    run env DEVDESK_FS_FIND_MAX=1 "$REPO/bin/devdesk" attach --fs-find alpha
+    [ "$status" -eq 0 ]
+    [ "$(jq -r '[(.files | length), .truncated] | @tsv' <<<"$output")" = "$(printf '1\ttrue')" ]
+    run env DEVDESK_FS_LIST_MAX=5 "$REPO/bin/devdesk" attach --fs-list alpha src
+    [ "$status" -eq 0 ]
+    [ "$(jq -r '[(.entries | length), .truncated] | @tsv' <<<"$output")" = "$(printf '5\ttrue')" ]
+}
+
+# Save through --fs-write the way the browser does: content as base64 on stdin.
+fs_write() { # SESSION PATH BASE CONTENT-FILE
+    local size
+    size=$(stat -c %s "$4")
+    base64 -w0 "$4" | devdesk attach --fs-write "$1" "$2" "$size" "$3"
+}
+
+@test "fs-write saves atomically, keeps the mode, and refuses stale bases (#20)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    printf 'v1\n' >"$p/conf.sh"
+    chmod 0750 "$p/conf.sh"
+    base=$(sha256sum "$p/conf.sh" | cut -d' ' -f1)
+    printf 'v2\n' >"$TMP/new"
+    run fs_write alpha conf.sh "$base" "$TMP/new"
+    [ "$status" -eq 0 ]
+    [ "$(tail -n1 <<<"$output" | jq -r '.ok')" = true ]
+    [ "$(cat "$p/conf.sh")" = v2 ]
+    [ "$(stat -c %a "$p/conf.sh")" = 750 ]
+    [ "$(tail -n1 <<<"$output" | jq -r '.sha')" = "$(sha256sum "$p/conf.sh" | cut -d' ' -f1)" ]
+    # Someone (Claude) changed it since: the old base no longer matches.
+    printf 'v3 from me\n' >"$TMP/mine"
+    run fs_write alpha conf.sh "$base" "$TMP/mine"
+    [ "$(tail -n1 <<<"$output" | jq -r '[.ok, .conflict] | @tsv')" = "$(printf 'false\ttrue')" ]
+    [ "$(cat "$p/conf.sh")" = v2 ]
+    # No temp files left behind
+    [ -z "$(find "$p" -name '*.devdesk-*')" ]
+    # Empty files are fine
+    : >"$TMP/empty"
+    base=$(sha256sum "$p/conf.sh" | cut -d' ' -f1)
+    run fs_write alpha conf.sh "$base" "$TMP/empty"
+    [ "$(tail -n1 <<<"$output" | jq -r '.ok')" = true ]
+    [ ! -s "$p/conf.sh" ]
+}
+
+@test "fs-write creates new files (and folders) but never overwrites or escapes (#20)" {
+    p="$DEVDESK_PROJECTS_ROOT/alpha"
+    printf 'hello\n' >"$TMP/c"
+    run fs_write alpha docs/notes/new.md new "$TMP/c"
+    [ "$(tail -n1 <<<"$output" | jq -r '[.ok, .path] | @tsv')" = "$(printf 'true\tdocs/notes/new.md')" ]
+    [ "$(cat "$p/docs/notes/new.md")" = hello ]
+    run fs_write alpha docs/notes/new.md new "$TMP/c"
+    [ "$status" -ne 0 ]
+    [[ $output == *"already exists"* ]]
+    ln -s "$TMP/outside" "$p/out"
+    for bad in ../escape.txt /etc/x out/pwned.txt out/newdir/x.txt docs/ ""; do
+        run fs_write alpha "$bad" new "$TMP/c"
+        [ "$status" -ne 0 ]
+    done
+    [ ! -e "$TMP/outside/pwned.txt" ] && [ ! -e "$TMP/outside/newdir" ] && [ ! -e "$DEVDESK_PROJECTS_ROOT/escape.txt" ]
+    # A short stream fails without touching anything
+    run bash -c "printf aGVs | '$REPO/bin/devdesk' attach --fs-write alpha docs/notes/new.md 6 $(sha256sum "$p/docs/notes/new.md" | cut -d' ' -f1)"
+    [ "$status" -ne 0 ]
+    [ "$(cat "$p/docs/notes/new.md")" = hello ]
+}
@@ -2,6 +2,7 @@
 // file and nothing else), with CSS, JS, fonts and the favicon all inlined.
 import { build, transform } from 'esbuild';
 import { readFile, writeFile, mkdir } from 'node:fs/promises';
+import { createHash } from 'node:crypto';
 import { dirname, join } from 'node:path';
 import { fileURLToPath } from 'node:url';

@@ -33,8 +34,29 @@ async function fontFaces(weights) {
  return faces.join('\n');
 }

+// The file viewer's editor (devdesk#19): its own IIFE, served over the ttyd
+// channel by `devdesk attach --asset editor.js` and cached by the browser. The
+// page carries its SHA-256, which is both the integrity check and the cache key.
+async function editorBundle() {
+  const out = await build({
+    entryPoints: [at('web', 'editor', 'index.js')],
+    bundle: true,
+    minify: true,
+    format: 'iife',
+    globalName: 'DevDeskEditor',
+    target: ['es2020'],
+    write: false,
+    legalComments: 'eof',
+  });
+  const code = out.outputFiles[0].text;
+  await mkdir(at('dist', 'assets'), { recursive: true });
+  await writeFile(at('dist', 'assets', 'editor.js'), code);
+  return { sha: createHash('sha256').update(code).digest('hex'), size: Buffer.byteLength(code) };
+}
+
 async function main() {
  const ver = await version();
+  const editor = await editorBundle();

  const js = await build({
    entryPoints: [at('web', 'src', 'main.js')],
@@ -44,7 +66,10 @@ async function main() {
    target: ['es2020'],
    write: false,
    legalComments: 'eof',
-    define: { __DEVDESK_VERSION__: JSON.stringify(ver) },
+    define: {
+      __DEVDESK_VERSION__: JSON.stringify(ver),
+      __EDITOR_SHA__: JSON.stringify(editor.sha),
+    },
  });

  const css = await transform([
@@ -67,6 +92,7 @@ async function main() {
  await mkdir(at('dist'), { recursive: true });
  await writeFile(at('dist', 'index.html'), html);
  console.log(`dist/index.html  ${(html.length / 1024).toFixed(0)} KiB  (devdesk ${ver})`);
+  console.log(`dist/assets/editor.js  ${(editor.size / 1024).toFixed(0)} KiB  sha256 ${editor.sha.slice(0, 12)}`);
 }

 main().catch((err) => {
@@ -0,0 +1,187 @@
+// The file viewer's editor bundle (devdesk#19): CodeMirror 6 with stream-mode
+// languages, a unified diff view, and markdown rendering. Built separately to
+// dist/assets/editor.js (window.DevDeskEditor) and loaded over the ttyd channel
+// the first time the Files pane opens, so the page itself stays small.
+import { EditorView, keymap, lineNumbers, highlightActiveLine, highlightActiveLineGutter, drawSelection, highlightSpecialChars } from '@codemirror/view';
+import { EditorState } from '@codemirror/state';
+import { defaultKeymap, history, historyKeymap, indentWithTab } from '@codemirror/commands';
+import { syntaxHighlighting, HighlightStyle, StreamLanguage, bracketMatching, foldGutter, foldKeymap } from '@codemirror/language';
+import { search, searchKeymap, highlightSelectionMatches } from '@codemirror/search';
+import { markdownLanguage } from '@codemirror/lang-markdown';
+import { unifiedMergeView } from '@codemirror/merge';
+import { tags as t } from '@lezer/highlight';
+import { shell } from '@codemirror/legacy-modes/mode/shell';
+import { python } from '@codemirror/legacy-modes/mode/python';
+import { javascript, json, typescript } from '@codemirror/legacy-modes/mode/javascript';
+import { yaml } from '@codemirror/legacy-modes/mode/yaml';
+import { toml } from '@codemirror/legacy-modes/mode/toml';
+import { properties } from '@codemirror/legacy-modes/mode/properties';
+import { nginx } from '@codemirror/legacy-modes/mode/nginx';
+import { diff as diffMode } from '@codemirror/legacy-modes/mode/diff';
+import { css } from '@codemirror/legacy-modes/mode/css';
+import { xml, html } from '@codemirror/legacy-modes/mode/xml';
+import { go } from '@codemirror/legacy-modes/mode/go';
+import { rust } from '@codemirror/legacy-modes/mode/rust';
+import { standardSQL } from '@codemirror/legacy-modes/mode/sql';
+import { dockerFile } from '@codemirror/legacy-modes/mode/dockerfile';
+import { lua } from '@codemirror/legacy-modes/mode/lua';
+import { perl } from '@codemirror/legacy-modes/mode/perl';
+import { ruby } from '@codemirror/legacy-modes/mode/ruby';
+import { marked } from 'marked';
+import DOMPurify from 'dompurify';
+
+const MODES = {
+  shell, python, javascript, json, typescript, yaml, toml, properties, nginx, diff: diffMode, css, xml, html,
+  go, rust, sql: standardSQL, dockerfile: dockerFile, lua, perl, ruby,
+};
+
+const BY_EXT = {
+  md: 'markdown', markdown: 'markdown', mdx: 'markdown',
+  sh: 'shell', bash: 'shell', zsh: 'shell', ksh: 'shell', env: 'shell', bats: 'shell',
+  py: 'python', pyi: 'python',
+  js: 'javascript', mjs: 'javascript', cjs: 'javascript', jsx: 'javascript',
+  ts: 'typescript', tsx: 'typescript', mts: 'typescript',
+  json: 'json', jsonc: 'json', webmanifest: 'json',
+  yml: 'yaml', yaml: 'yaml',
+  toml: 'toml',
+  ini: 'properties', cfg: 'properties', conf: 'properties', properties: 'properties',
+  service: 'properties', timer: 'properties', socket: 'properties', mount: 'properties', network: 'properties',
+  diff: 'diff', patch: 'diff',
+  css: 'css', scss: 'css',
+  xml: 'xml', svg: 'xml', plist: 'xml',
+  html: 'html', htm: 'html', php: 'html', j2: 'html', jinja: 'html',
+  go: 'go', rs: 'rust', sql: 'sql', lua: 'lua', pl: 'perl', pm: 'perl', rb: 'ruby',
+};
+
+// Language for a path: extension, a few well-known names, else none.
+export function languageFor(path) {
+  const name = path.split('/').pop().toLowerCase();
+  if (name === 'dockerfile' || name.startsWith('dockerfile.') || name.endsWith('.dockerfile')) return 'dockerfile';
+  if (name === 'makefile' || name === 'gnumakefile') return 'shell';
+  if (/(^|\/)nginx\//.test(path) || name === 'nginx.conf') return 'nginx';
+  if (['.bashrc', '.profile', '.bash_profile', '.zshrc', 'pkgbuild'].includes(name)) return 'shell';
+  if (name.startsWith('.env')) return 'shell';
+  const ext = name.includes('.') ? name.split('.').pop() : '';
+  return BY_EXT[ext] ?? null;
+}
+
+function languageExtension(lang) {
+  if (lang === 'markdown') return markdownLanguage;
+  if (lang && MODES[lang]) return StreamLanguage.define(MODES[lang]);
+  return [];
+}
+
+// Colours come from the page's TDS variables, so dark/light mode just works.
+const highlight = HighlightStyle.define([
+  { tag: [t.keyword, t.controlKeyword, t.operatorKeyword, t.modifier], color: 'var(--accent-orange)' },
+  { tag: [t.string, t.special(t.string), t.regexp], color: 'var(--accent-green)' },
+  { tag: [t.comment, t.lineComment, t.blockComment, t.meta], color: 'var(--text-muted)', fontStyle: 'italic' },
+  { tag: [t.number, t.bool, t.atom, t.null], color: 'var(--accent-purple)' },
+  { tag: [t.typeName, t.className, t.namespace], color: 'var(--accent-amber)' },
+  { tag: [t.function(t.variableName), t.function(t.propertyName), t.definition(t.variableName)], color: 'var(--accent-cyan)' },
+  { tag: [t.propertyName, t.attributeName], color: 'var(--accent-cyan)' },
+  { tag: [t.tagName], color: 'var(--accent-orange)' },
+  { tag: [t.heading, t.heading1, t.heading2, t.heading3], color: 'var(--accent-cyan)', fontWeight: 'bold' },
+  { tag: t.strong, fontWeight: 'bold' },
+  { tag: t.emphasis, fontStyle: 'italic' },
+  { tag: t.strikethrough, textDecoration: 'line-through' },
+  { tag: [t.link, t.url], color: 'var(--accent-cyan)', textDecoration: 'underline' },
+  { tag: [t.monospace], color: 'var(--accent-amber)' },
+  { tag: [t.quote], color: 'var(--text-secondary)', fontStyle: 'italic' },
+  { tag: t.inserted, color: 'var(--accent-green)' },
+  { tag: t.deleted, color: 'var(--accent-red)' },
+  { tag: t.invalid, color: 'var(--accent-red)' },
+]);
+
+const theme = EditorView.theme({
+  '&': { height: '100%', color: 'var(--text-primary)', backgroundColor: 'var(--bg-terminal)', fontSize: 'var(--dd-editor-font, 13px)' },
+  '.cm-scroller': { fontFamily: 'var(--font-mono)', lineHeight: '1.5' },
+  '.cm-content': { caretColor: 'var(--accent-orange)' },
+  '.cm-cursor': { borderLeftColor: 'var(--accent-orange)' },
+  '.cm-gutters': { backgroundColor: 'var(--bg-secondary)', color: 'var(--text-dim)', border: 'none', borderRight: '1px solid var(--border-dim)' },
+  '.cm-activeLine': { backgroundColor: 'var(--accent-cyan-dim)' },
+  '.cm-activeLineGutter': { backgroundColor: 'var(--accent-cyan-dim)', color: 'var(--accent-cyan)' },
+  '&.cm-focused .cm-selectionBackground, .cm-selectionBackground, ::selection': { backgroundColor: 'rgba(0, 150, 220, 0.28) !important' },
+  '.cm-searchMatch': { backgroundColor: 'var(--accent-amber-dim)', outline: '1px solid var(--accent-amber)' },
+  '.cm-searchMatch.cm-searchMatch-selected': { backgroundColor: 'var(--accent-orange-dim)' },
+  '.cm-selectionMatch': { backgroundColor: 'var(--accent-cyan-dim)' },
+  '.cm-panels': { backgroundColor: 'var(--bg-secondary)', color: 'var(--text-primary)', borderColor: 'var(--border-color)' },
+  '.cm-panel input, .cm-panel button': { fontFamily: 'var(--font-mono)', fontSize: '12px' },
+  '.cm-textfield': { backgroundColor: 'var(--bg-input)', color: 'var(--text-primary)', border: '1px solid var(--border-color)' },
+  '.cm-button': { backgroundImage: 'none', backgroundColor: 'var(--bg-tertiary)', color: 'var(--text-primary)', border: '1px solid var(--border-color)' },
+  '.cm-foldGutter span': { color: 'var(--text-dim)' },
+  // unified diff
+  '.cm-changedLine': { backgroundColor: 'var(--accent-green-dim) !important' },
+  '.cm-changedText': { backgroundColor: 'rgba(0, 200, 120, 0.22) !important' },
+  '.cm-deletedChunk': { backgroundColor: 'var(--accent-red-dim) !important' },
+  '.cm-deletedChunk .cm-deletedText, .cm-deletedChunk del': { backgroundColor: 'rgba(255, 45, 85, 0.22)', textDecoration: 'none' },
+  '.cm-insertedLine': { backgroundColor: 'var(--accent-green-dim)' },
+  '.cm-changeGutter': { width: '3px' },
+  '.cm-changedLineGutter': { backgroundColor: 'var(--accent-green)' },
+  '.cm-deletedLineGutter': { backgroundColor: 'var(--accent-red)' },
+});
+
+function baseExtensions(path, { readOnly = true, wrap = false } = {}) {
+  return [
+    lineNumbers(), foldGutter(), highlightSpecialChars(), highlightActiveLine(), highlightActiveLineGutter(),
+    drawSelection(), history(), search({ top: true }), highlightSelectionMatches(), bracketMatching(),
+    syntaxHighlighting(highlight), theme, languageExtension(languageFor(path)),
+    // Read-only document in an editable view: the caret, selection, arrow keys
+    // and Ctrl+F work, typing doesn't; no on-screen keyboard on phones.
+    EditorState.readOnly.of(readOnly),
+    readOnly ? EditorView.contentAttributes.of({ inputmode: 'none' }) : [],
+    keymap.of([...defaultKeymap, ...historyKeymap, ...searchKeymap, ...foldKeymap]),
+    wrap ? EditorView.lineWrapping : [],
+  ];
+}
+
+// Read-only view of a file.
+export function viewer(parent, { doc, path, wrap }) {
+  const view = new EditorView({ parent, state: EditorState.create({ doc, extensions: baseExtensions(path, { wrap }) }) });
+  return { view, destroy: () => view.destroy() };
+}
+
+// Editable file (devdesk#20): onChange(text) after every edit, onSave() on
+// Ctrl/Cmd+S (which never reaches the browser or the terminal).
+export function editor(parent, { doc, path, wrap, onChange, onSave }) {
+  const view = new EditorView({
+    parent,
+    state: EditorState.create({
+      doc,
+      extensions: [
+        keymap.of([{ key: 'Mod-s', preventDefault: true, run: () => { onSave?.(); return true; } }, indentWithTab]),
+        baseExtensions(path, { readOnly: false, wrap }),
+        EditorView.updateListener.of((update) => {
+          if (update.docChanged) onChange?.(update.state.doc.toString());
+        }),
+      ],
+    }),
+  });
+  return {
+    view,
+    text: () => view.state.doc.toString(),
+    // Replace the whole document (reload from disk) keeping the cursor roughly where it was.
+    setText: (text) => {
+      const pos = Math.min(view.state.selection.main.head, text.length);
+      view.dispatch({ changes: { from: 0, to: view.state.doc.length, insert: text }, selection: { anchor: pos } });
+    },
+    destroy: () => view.destroy(),
+  };
+}
+
+// Unified diff of the HEAD version against the working copy.
+export function diff(parent, { original, modified, path, wrap }) {
+  const view = new EditorView({
+    parent,
+    state: EditorState.create({
+      doc: modified,
+      extensions: [baseExtensions(path, { wrap }), unifiedMergeView({ original, mergeControls: false, highlightChanges: true, gutter: true })],
+    }),
+  });
+  return { view, destroy: () => view.destroy() };
+}
+
+// Markdown to sanitized HTML (shown in a sandboxed iframe on top of this).
+export function markdown(text) {
+  return DOMPurify.sanitize(marked.parse(text, { gfm: true, breaks: false }), { USE_PROFILES: { html: true } });
+}
@@ -63,11 +63,13 @@
        </div>
        <button type="button" class="dd-menu-item" id="theme-menu" role="menuitem">Light mode</button>
        <button type="button" class="dd-menu-item" id="notify-toggle" role="menuitem">Desktop notifications</button>
+        <button type="button" class="dd-menu-item" id="palette-menu" role="menuitem">Command palette</button>
        <button type="button" class="dd-menu-item" id="help-open" role="menuitem">Keyboard shortcuts</button>
        <button type="button" class="dd-menu-item" id="fullscreen-toggle" role="menuitem" title="In Chromium, fullscreen also captures Ctrl+W/Ctrl+T for the terminal">Fullscreen</button>
        <div class="dd-menu-foot" id="version">devdesk</div>
      </div>
    </div>
+    <button type="button" class="lt-btn lt-btn-sm dd-files-toggle" id="files-toggle" aria-controls="files" aria-expanded="false" title="Files: browse, preview and diff this session's folder (Ctrl+Shift+E)"><span class="dd-panels-label">Files</span><span class="dd-panels-icon" aria-hidden="true">🗀</span></button>
    <button type="button" class="lt-btn lt-btn-sm dd-panels" id="sidebar-toggle" aria-controls="sidebar" aria-expanded="false"><span class="dd-panels-label">Panels</span><span class="dd-panels-icon" aria-hidden="true">▤</span></button>
  </div>
 </header>
@@ -88,6 +90,30 @@
    </div>
  </section>

+  <section class="lt-frame dd-files" id="files" aria-label="Files" hidden>
+    <div class="dd-files-resizer" id="files-resizer" role="separator" aria-orientation="vertical" aria-label="Resize the files pane" tabindex="0"></div>
+    <div class="dd-files-head">
+      <button type="button" class="dd-icon-btn dd-explorer-toggle" title="Show / hide the explorer" aria-label="Toggle explorer">☰</button>
+      <div class="dd-tabs" role="tablist" aria-label="Open files"></div>
+      <span class="dd-files-actions">
+        <button type="button" class="dd-icon-btn dd-files-new" title="New file" aria-label="New file">＋</button>
+        <button type="button" class="dd-icon-btn dd-files-find" title="Go to file (Ctrl+P)" aria-label="Go to file">⌕</button>
+        <button type="button" class="dd-icon-btn dd-files-refresh" title="Refresh" aria-label="Refresh">↻</button>
+        <button type="button" class="dd-icon-btn dd-files-close" title="Close (Esc)" aria-label="Close files">✕</button>
+      </span>
+    </div>
+    <div class="dd-files-main">
+      <div class="dd-explorer">
+        <div class="dd-explorer-views" role="tablist">
+          <button type="button" role="tab" data-files-view="explorer" aria-selected="true">Explorer</button>
+          <button type="button" role="tab" data-files-view="changes" aria-selected="false">Changes <span class="dd-files-count"></span></button>
+        </div>
+        <div class="dd-explorer-body" role="tree" aria-label="Files"></div>
+      </div>
+      <div class="dd-editor-area"></div>
+    </div>
+  </section>
+
  <div class="dd-backdrop" id="backdrop" hidden></div>
  <aside id="sidebar" class="dd-sidebar" aria-label="Panels">
    <section class="lt-frame dd-widget" id="widget-sessions" data-state="live">
@@ -152,13 +152,21 @@ async function runCommandNow(args, timeoutMs) {
      clearTimeout(timer);
      resolve(new TextDecoder().decode(concat(chunks)));
    };
+    const decoder = new TextDecoder();
+    let head = '';
+    let tail = '';
    socket.onmessage = (event) => {
      const { type, payload } = decodeServer(event.data);
      if (type !== Server.OUTPUT) return;
      chunks.push(payload.slice());
+      const piece = decoder.decode(payload, { stream: true });
+      if (head.length < 4096) head += piece;
+      tail = (tail + piece).slice(-64);
      // Hang up as soon as the answer is complete: devdesk waits for that
      // before exiting, so ttyd can't drop its last output (devdesk#35).
-      if (isComplete(new TextDecoder().decode(concat(chunks)))) {
+      // Replies are one JSON line (or a devdesk: error), so only a chunk that
+      // ends a line with "}" is worth a full parse; big replies stay linear.
+      if (/^devdesk: .*\n/m.test(head) || (/\}\s*\n\s*$/.test(tail) && isComplete(new TextDecoder().decode(concat(chunks))))) {
        finish();
        socket.close();
      }
@@ -201,11 +209,28 @@ export function uploadFile(session, file, onProgress) {
 }

 async function uploadNow(session, file, onProgress) {
-  const token = await fetchToken();
  const name = (file.name || 'pasted-image.png').slice(-100);
+  const result = await streamIn(['--upload', session, name, String(file.size)], 'DEVDESK-UPLOAD-READY', file, onProgress);
+  if (!result.ok || !result.path) throw new Error('upload failed');
+  return result.path;
+}
+
+// Save a file from the editor (devdesk#20): `--fs-write SESSION PATH BYTES BASE`
+// with the content streamed after the ready line. Resolves the server's JSON:
+// {ok: true, sha, size, mtime} or {ok: false, conflict: true, sha} when the file
+// changed since `base` (a sha256, or "new" to create).
+export function writeFile(session, path, bytes, base) {
+  return limited(() => streamIn(['--fs-write', session, path, String(bytes.length), base], 'DEVDESK-WRITE-READY', new Blob([bytes])));
+}
+
+// Run a devdesk command that reads base64 from the terminal after printing
+// `ready`: stream `blob` in slices (never all in memory), then resolve the JSON
+// reply. Fails on 20 s of inactivity rather than a fixed total (devdesk#9).
+async function streamIn(args, ready, blob, onProgress) {
+  const token = await fetchToken();
  const slice = 3 * 16 * 1024; // multiple of 3: base64 of slices concatenates cleanly
  return new Promise((resolve, reject) => {
-    const socket = new WebSocket(wsUrl(window.location, ['--upload', session, name, String(file.size)]), ['tty']);
+    const socket = new WebSocket(wsUrl(window.location, args), ['tty']);
    socket.binaryType = 'arraybuffer';
    const decoder = new TextDecoder();
    let output = '';
@@ -216,15 +241,16 @@ async function uploadNow(session, file, onProgress) {
      idle = setTimeout(() => socket.close(), 20000);
    };
    const send = async () => {
-      for (let offset = 0; offset < file.size; offset += slice) {
+      for (let offset = 0; offset < blob.size; offset += slice) {
        while (socket.bufferedAmount > 1 << 20) await sleep(20);
        if (socket.readyState !== WebSocket.OPEN) return;
-        const bytes = new Uint8Array(await file.slice(offset, offset + slice).arrayBuffer());
+        const bytes = new Uint8Array(await blob.slice(offset, offset + slice).arrayBuffer());
        socket.send(encodeInput(toBase64(bytes)));
        touch();
-        onProgress?.(Math.min(1, (offset + slice) / file.size));
+        onProgress?.(Math.min(1, (offset + slice) / blob.size));
      }
    };
+    const after = () => output.slice(output.indexOf(ready) + ready.length);
    touch();
    socket.onopen = () => socket.send(encodeInit(token, 240, 24));
    socket.onmessage = (event) => {
@@ -232,28 +258,91 @@ async function uploadNow(session, file, onProgress) {
      const { type, payload } = decodeServer(event.data);
      if (type !== Server.OUTPUT) return;
      output += decoder.decode(payload, { stream: true });
-      if (!sending && output.includes('DEVDESK-UPLOAD-READY')) {
+      if (!sending && output.includes(ready)) {
        sending = true;
        send();
-      } else if (sending && isComplete(output.replace(/^[\s\S]*DEVDESK-UPLOAD-READY/, ''))) {
+      }
+      if (sending && isComplete(after())) {
        socket.close(); // the reply is in; let devdesk exit (devdesk#35)
      }
    };
    socket.onerror = () => {};
    socket.onclose = () => {
      clearTimeout(idle);
-      const text = stripAnsi(output.replace(/^[\s\S]*DEVDESK-UPLOAD-READY/, ''));
+      const text = stripAnsi(output.includes(ready) ? after() : output);
      try {
-        const result = parseListOutput(text);
-        if (result.ok && result.path) {
-          resolve(result.path);
-          return;
-        }
+        resolve(parseListOutput(text));
+        return;
      } catch {
        // fall through to the error message
      }
      const message = text.split(/\r?\n/).map((l) => l.trim()).filter(Boolean).pop();
-      reject(new Error((message || 'upload failed').replace(/^devdesk:\s*/, '')));
+      reject(new Error((message || 'no reply').replace(/^devdesk:\s*/, '')));
+    };
+  });
+}
+
+// Blob replies (`--fs-read`, `--git-show`, `--asset`): a JSON header line, then
+// base64 between DEVDESK-BLOB-BEGIN/END. Resolves { header, base64 }, base64
+// being null when the file has no body (too large, binary). Only the head and
+// the tail of the stream are decoded while it arrives, so megabytes stay cheap.
+export function runBlob(args, timeoutMs = 30000) {
+  return limited(() => runBlobNow(args, timeoutMs));
+}
+
+async function runBlobNow(args, timeoutMs) {
+  const token = await fetchToken();
+  return new Promise((resolve, reject) => {
+    const socket = new WebSocket(wsUrl(window.location, args), ['tty']);
+    socket.binaryType = 'arraybuffer';
+    const chunks = [];
+    const decoder = new TextDecoder();
+    let head = '';
+    let tail = '';
+    let settled = false;
+    const done = (fn, value) => {
+      if (settled) return;
+      settled = true;
+      clearTimeout(timer);
+      socket.close();
+      fn(value);
+    };
+    const timer = setTimeout(() => done(reject, new Error('devdesk did not answer in time')), timeoutMs);
+    const finish = () => {
+      const text = stripAnsi(new TextDecoder().decode(concat(chunks)));
+      const error = /^devdesk: (.*)$/m.exec(text);
+      const line = text.split(/\r?\n/).find((l) => l.startsWith('{'));
+      if (!line) {
+        done(reject, new Error(error ? error[1] : 'no reply'));
+        return;
+      }
+      let header;
+      try {
+        header = JSON.parse(line);
+      } catch {
+        done(reject, new Error('unreadable reply'));
+        return;
+      }
+      const body = /DEVDESK-BLOB-BEGIN\r?\n([\s\S]*?)\r?\nDEVDESK-BLOB-END/.exec(text);
+      done(resolve, { header, base64: body ? body[1].replace(/\s+/g, '') : null });
+    };
+    socket.onopen = () => socket.send(encodeInit(token, 240, 24));
+    socket.onmessage = (event) => {
+      const { type, payload } = decodeServer(event.data);
+      if (type !== Server.OUTPUT) return;
+      chunks.push(payload.slice());
+      const piece = decoder.decode(payload, { stream: true });
+      if (head.length < 4096) head += piece;
+      tail = (tail + piece).slice(-256);
+      const firstLine = /^\s*(\{.*\})\r?$/m.exec(head);
+      if (tail.includes('DEVDESK-BLOB-END') || /^devdesk: .*\n/m.test(head)
+          || (firstLine && !head.includes('DEVDESK-BLOB-BEGIN') && /"tooLarge":true/.test(firstLine[1]))) {
+        finish();
+      }
+    };
+    socket.onerror = () => {};
+    socket.onclose = () => {
+      if (!settled) finish();
    };
  });
 }
@@ -8,11 +8,12 @@ import { ago } from './sessions.js';

 const KEY = 'devdesk.inbox';
 const MAX = 30;
+const MAX_AGE = 7 * 86400 * 1000;

 function load() {
  try {
    const list = JSON.parse(localStorage.getItem(KEY) || '[]');
-    return Array.isArray(list) ? list : [];
+    return Array.isArray(list) ? list.filter((e) => Date.now() - e.at < MAX_AGE) : [];
  } catch {
    return [];
  }
@@ -45,6 +46,7 @@ export class Inbox {
    this.events = load();
    this.waiting = [];
    this.alerts = [];
+    this.known = null; // session names that exist, once the list has loaded
    this.list = panel.querySelector('.lt-notif-panel-list');
    panel.querySelector('.lt-notif-panel-clear').addEventListener('click', () => this.markAllRead());
    window.addEventListener('storage', (event) => {
@@ -78,9 +80,10 @@ export class Inbox {
  }

  // Live state: other sessions waiting on you, firing alerts.
-  setLive({ waiting, alerts }) {
+  setLive({ waiting, alerts, sessions }) {
    if (waiting) this.waiting = waiting;
    if (alerts) this.alerts = alerts;
+    if (sessions) this.known = new Set(sessions);
    this.render();
  }

@@ -91,7 +94,7 @@ export class Inbox {
  }

  unread() {
-    return this.events.filter((e) => !e.read && e.kind !== 'waiting').length;
+    return this.events.filter((e) => !e.read && e.kind !== 'waiting' && !(this.known && e.session && !e.url && !this.known.has(e.session))).length;
  }

  render() {
@@ -155,12 +158,16 @@ export class Inbox {
      nodes.push(el('div', { class: 'dd-notif-section' }, 'Recent'));
      for (const e of recent.slice(0, 12)) {
        const kind = KINDS[e.kind] ?? { tone: 'cyan' };
+        // An entry about a session that has since ended must not bring it back (devdesk#38).
+        const ended = !e.url && e.session && this.known && !this.known.has(e.session);
        nodes.push(item({
-          dot: e.read ? 'read' : kind.tone, unread: !e.read, title: e.text, meta: when(e.at),
+          dot: e.read || ended ? 'read' : kind.tone, unread: !e.read && !ended, title: e.text,
+          meta: `${when(e.at)}${ended ? ' · session ended' : ''}`,
          onclick: close(() => {
            this.events = this.events.map((x) => (x.id === e.id ? { ...x, read: true } : x));
            save(this.events);
            if (e.url) window.open(e.url, '_blank', 'noopener');
+            else if (ended) this.hooks.ended?.(e.session);
            else if (e.session) this.hooks.openSession(e.session);
          }),
        }));
@@ -12,6 +12,7 @@ import { bindAskClaude } from './widgets.js';
 import { heardWithin, onShared, share } from './shared.js';
 import { CommandPalette, dialogOpen, openDialog, toast } from './ui.js';
 import { Inbox } from './inbox.js';
+import { FilesPane } from './files.js';
 import { el } from './dom.js';
 import * as notify from './notify.js';

@@ -57,6 +58,8 @@ const ui = {
 };

 const urlSession = sessionFromSearch(window.location.search);
+// Notification links (Matrix) add existing=1: open, never re-create (devdesk#38).
+const urlExisting = new URLSearchParams(window.location.search).get('existing') === '1';
 const state = {
  session: urlSession, // null = picker
  conn: null,
@@ -75,6 +78,7 @@ let fit;
 let sessionsPanel;
 let palette;
 let inbox;
+let files;
 let lastRepo = null;
 let lastAlerts = null;
 let waitingOthers = [];
@@ -167,7 +171,11 @@ function recordTransitions(sessions) {
 }

 function renderPanelsBadge() {
-  inbox?.setLive({ waiting: waitingOthers, alerts: lastAlerts?.alerts ?? [] });
+  inbox?.setLive({
+    waiting: waitingOthers,
+    alerts: lastAlerts?.alerts ?? [],
+    sessions: sessionsPanel?.data ? sessionsPanel.data.sessions.map((x) => x.name) : null,
+  });
 }

 function onSessionData({ fetched = false } = {}) {
@@ -314,14 +322,19 @@ function updateUrl(session) {
  const url = new URL(window.location.href);
  if (session) url.searchParams.set('arg', session);
  else url.searchParams.delete('arg');
+  url.searchParams.delete('existing');
  if (url.href !== window.location.href) window.history.replaceState(null, '', url);
 }

 // ---------------------------------------------------------------- connection

-// reconnect: automatic re-attach after a drop. It must not re-create a session
-// that was ended or renamed meanwhile, so it asks for --existing (devdesk#4).
-function connect(session, { reconnect = false } = {}) {
+// existing: go to a session that should already exist (reconnects, the
+// switcher, inbox entries, notification links). It must not re-create one that
+// was ended or renamed meanwhile, so it asks for --existing (devdesk#4, #38).
+// Creating is explicit: a typed name, the New dialog, the picker, recents.
+function connect(session, { existing = false, reconnect = false } = {}) {
+  const existingOnly = Boolean(session) && (existing || reconnect);
+  state.existingOnly = existingOnly;
  clearTimeout(state.retryTimer);
  state.conn?.dispose();
  state.session = session;
@@ -330,13 +343,14 @@ function connect(session, { reconnect = false } = {}) {
  paneTitleRaw = '';
  renderPaneTitle();
  onSessionData();
+  files?.sessionChanged();
  hideOverlay();
  setWsState('connecting', 'connecting');
  state.openedAt = 0;
  term.reset();

  const conn = new TtydConnection({
-    arg: session && reconnect ? ['--existing', session] : session,
+    arg: existingOnly ? ['--existing', session] : session,
    size: () => ({ cols: term.cols, rows: term.rows }),
    onOpen: () => {
      state.openedAt = Date.now();
@@ -370,6 +384,25 @@ function onClosed(code) {
  // few seconds of opening means the session could not start (the reason is
  // printed in the terminal), so don't retry forever.
  const failedFast = code !== 1000 && Date.now() - state.openedAt < 4000;
+  if (failedFast && state.existingOnly) {
+    // Most likely ended or renamed since the link was made: say so, and only
+    // start it again when asked.
+    const name = state.session;
+    sessionsPanel?.reload().then(() => {
+      const known = sessionsPanel.data?.sessions?.some((x) => x.name === name);
+      if (known) {
+        scheduleReconnect();
+        return;
+      }
+      setWsState('disconnected', 'ended');
+      showOverlay({
+        title: `${name} has ended`,
+        text: `The session "${name}" no longer exists: it was ended or renamed. Its conversation is still in Claude's history.`,
+        actions: [pickerAction, { label: `Start ${name} again`, run: () => connect(name) }],
+      });
+    });
+    return;
+  }
  if (failedFast) {
    showOverlay({
      title: 'Session did not start',
@@ -465,6 +498,7 @@ function applyTitle() {
    sessionsPanel.setCurrent(parsed.session);
    onSessionData();
    refreshRepo();
+    files?.sessionChanged();
  }
  paneTitleRaw = parsed.pane;
  renderPaneTitle();
@@ -511,7 +545,7 @@ function renderSwitcher() {
    return el('button', {
      type: 'button', role: 'menuitem',
      class: `dd-menu-item dd-switch-item is-${status.key}${s.name === state.session ? ' is-current' : ''}`,
-      title: s.dir || '', onclick: choose(() => connect(s.name)),
+      title: s.dir || '', onclick: choose(() => connect(s.name, { existing: true })),
    },
    el('span', { class: `lt-dot ${status.dot}` }),
    el('span', { class: 'dd-switch-name' }, s.name),
@@ -536,6 +570,7 @@ function setFontSize(size) {
  const clamped = Math.min(24, Math.max(10, size));
  term.options.fontSize = clamped;
  store.set('fontSize', clamped);
+  document.documentElement.style.setProperty('--dd-editor-font', `${clamped - 1}px`);
  $('font-size').textContent = String(clamped);
  fit.fit();
 }
@@ -586,7 +621,7 @@ function buildCommands() {
    const status = sessionStatus(s);
    add({
      id: `switch:${s.name}`, group: 'Sessions', label: `Switch to ${s.name}`, hint: status.label, keywords: s.dir,
-      icon: status.key === 'waiting' ? '!' : s.running ? '●' : '○', run: () => connect(s.name),
+      icon: status.key === 'waiting' ? '!' : s.running ? '●' : '○', run: () => connect(s.name, { existing: true }),
    });
  }
  add({ id: 'new', group: 'Sessions', icon: '+', label: 'New session…', keywords: 'create open project', run: () => sessionsPanel.newDialog() });
@@ -607,6 +642,17 @@ function buildCommands() {
    add({ id: 'detach', group: 'Terminal', icon: '⏏', label: 'Detach (the session keeps running)', kbd: '^b d', run: () => sendKeys('\x02d') });
  }

+  if (state.session) {
+    add({ id: 'files', group: 'Files', icon: '🗀', label: files.isOpen ? 'Close files' : 'Browse files', kbd: 'Ctrl+⇧E', keywords: 'explorer folder read open view', run: () => files.toggle('files') });
+    add({ id: 'changes', group: 'Files', icon: '±', label: 'Review changes (git diff)', keywords: 'git status diff claude edits', run: () => files.open('changes') });
+    add({
+      id: 'goto-file', group: 'Files', icon: '⌕', label: 'Go to file…', kbd: 'Ctrl+P in Files', keywords: 'open find quick search',
+      run: () => {
+        files.open();
+        files.quickOpen.open();
+      },
+    });
+  }
  add({
    id: 'theme', group: 'View', icon: getTheme() === 'light' ? '◐' : '☀', keywords: 'theme light dark mode colour color',
    label: getTheme() === 'light' ? 'Switch to dark mode' : 'Switch to light mode', run: toggleTheme,
@@ -666,6 +712,9 @@ const KEY_HELP = [
  ]],
  ['DevDesk', [
    ['Ctrl+⇧ P', 'Command palette'],
+    ['Ctrl+⇧ E', 'Files: browse, preview, diff, edit (Esc closes)'],
+    ['Ctrl+P', 'Files: go to file'],
+    ['Ctrl+S', 'Files: save the open file'],
    ['Ctrl+⇧ C / V', 'Copy selection / paste'],
    ['⇧ drag', 'Select text in the browser'],
    ['Drop or paste a file', 'Upload it and attach it for Claude'],
@@ -681,6 +730,41 @@ function showHelp() {
  openDialog({ title: 'Keyboard shortcuts', body, actions: [{ label: 'Close', primary: true }] }).then(() => term.focus());
 }

+// Drag the files pane's left edge (or use ←/→ on it). The terminal keeps at
+// least ~60 columns; the width is remembered per browser.
+function wireResizer() {
+  const main = document.querySelector('.dd-main');
+  const handle = $('files-resizer');
+  const apply = (px) => {
+    const max = main.clientWidth - 520;
+    const width = Math.round(Math.max(340, Math.min(max, px)));
+    main.style.setProperty('--dd-files-w', `${width}px`);
+    return width;
+  };
+  const saved = Number(store.get('filesWidth', 0));
+  if (saved) apply(saved);
+  handle.addEventListener('pointerdown', (event) => {
+    event.preventDefault();
+    handle.setPointerCapture(event.pointerId);
+    ui.body.classList.add('dd-resizing');
+    const move = (e) => apply(main.getBoundingClientRect().right - e.clientX);
+    const up = () => {
+      ui.body.classList.remove('dd-resizing');
+      handle.removeEventListener('pointermove', move);
+      handle.removeEventListener('pointerup', up);
+      store.set('filesWidth', $('files').getBoundingClientRect().width);
+    };
+    handle.addEventListener('pointermove', move);
+    handle.addEventListener('pointerup', up);
+  });
+  handle.addEventListener('keydown', (event) => {
+    if (event.key !== 'ArrowLeft' && event.key !== 'ArrowRight') return;
+    event.preventDefault();
+    const width = apply($('files').getBoundingClientRect().width + (event.key === 'ArrowLeft' ? 40 : -40));
+    store.set('filesWidth', width);
+  });
+}
+
 async function toggleFullscreen() {
  if (document.fullscreenElement) {
    await document.exitFullscreen();
@@ -704,6 +788,7 @@ function renderNotifyButton() {
 }

 function setSidebar(open) {
+  if (open && files?.isOpen) files.close();
  ui.body.classList.toggle('dd-sidebar-open', open);
  ui.sidebarButton.setAttribute('aria-expanded', String(open));
  ui.backdrop.hidden = !(open && isNarrow());
@@ -765,10 +850,34 @@ function wireChrome() {
    showHelp();
  });
  $('footer-help').addEventListener('click', showHelp);
+  $('palette-menu').addEventListener('click', () => {
+    closeMenus();
+    palette.open();
+  });
+  files = new FilesPane($('files'), {
+    session: () => state.session,
+    paste: (text) => {
+      term.paste(text);
+    },
+    focusTerminal: () => term.focus(),
+    onToggle: (open) => {
+      ui.body.classList.toggle('dd-files-open', open);
+      $('files-toggle').setAttribute('aria-expanded', String(open));
+      if (open && ui.body.classList.contains('dd-sidebar-open')) setSidebar(false);
+    },
+  });
+  $('files-toggle').addEventListener('click', () => files.toggle());
+  wireResizer();
  palette = new CommandPalette(buildCommands);
  $('cmd-toggle').addEventListener('click', () => palette.open());
  // Ctrl+Shift+P (⌘⇧P): Ctrl+K belongs to the terminal (kill-line in Claude and bash).
  document.addEventListener('keydown', (event) => {
+    if ((event.ctrlKey || event.metaKey) && event.shiftKey && !event.altKey && event.code === 'KeyE') {
+      event.preventDefault();
+      event.stopPropagation();
+      if (state.session) files.toggle();
+      return;
+    }
    if ((event.ctrlKey || event.metaKey) && event.shiftKey && !event.altKey && event.code === 'KeyP') {
      event.preventDefault();
      event.stopPropagation();
@@ -789,7 +898,8 @@ function wireChrome() {
    badge: $('inbox-badge'),
    panel: $('inbox-panel'),
    hooks: {
-      openSession: (name) => connect(name),
+      openSession: (name) => connect(name, { existing: true }),
+      ended: (name) => toast.info(`${name} has ended; its conversation is still in Claude's history`),
      showAlerts: () => {
        setSidebar(true);
        $('widget-alerts').scrollIntoView({ block: 'start', behavior: 'smooth' });
@@ -819,6 +929,14 @@ function wireChrome() {
  // Esc closes menus and the narrow-screen drawer before the terminal sees it.
  document.addEventListener('keydown', (event) => {
    if (event.key !== 'Escape' || dialogOpen()) return;
+    // Files pane: Esc goes back / closes, unless the terminal or CodeMirror's
+    // own search panel has the focus.
+    if (files?.isOpen && !event.target.closest?.('.xterm, .cm-panels') && !menus.some(({ menu }) => !menu.hidden) && !inbox.isOpen) {
+      event.preventDefault();
+      event.stopPropagation();
+      files.escape();
+      return;
+    }
    const menuOpen = menus.some(({ menu }) => !menu.hidden) || inbox.isOpen;
    const drawerOpen = isNarrow() && ui.body.classList.contains('dd-sidebar-open');
    if (!menuOpen && !drawerOpen) return;
@@ -836,7 +954,7 @@ function wireChrome() {

  // Ctrl+W closes the tab before the terminal sees it; ask first.
  window.addEventListener('beforeunload', (event) => {
-    if (state.conn?.isOpen && state.session) {
+    if ((state.conn?.isOpen && state.session) || files?.hasDirty()) {
      event.preventDefault();
      event.returnValue = '';
    }
@@ -872,7 +990,7 @@ function wireChrome() {
    if (!document.hidden && ui.body.classList.contains('dd-sidebar-open')) refreshRepo();
  }, 60 * 1000);
  ui.attention.addEventListener('click', () => {
-    if (ui.attention.dataset.target) connect(ui.attention.dataset.target);
+    if (ui.attention.dataset.target) connect(ui.attention.dataset.target, { existing: true });
  });
 }

@@ -901,7 +1019,10 @@ async function boot() {
    theme: getTheme(),
    onShiftEnter: () => state.conn?.sendInput('\n'),
  }));
-  onThemeChange((theme) => { term.options.theme = THEMES[theme]; });
+  onThemeChange((theme) => {
+    term.options.theme = THEMES[theme];
+    files?.themeChanged();
+  });
  $('theme-toggle').addEventListener('click', toggleTheme);
  term.onData((data) => state.conn?.sendInput(data));
  term.onBinary((data) => state.conn?.sendBinary(data));
@@ -914,6 +1035,7 @@ async function boot() {
    notify.ring(state.session, ui.paneTitle.textContent || 'Claude needs your attention');
    refreshSoon(); // Claude finished a turn: states and context just changed
    setTimeout(refreshRepo, 2000); // …and maybe committed or pushed
+    setTimeout(() => files?.claudeTurnEnded(), 1200); // …or edited files
  });

  let fitFrame = 0;
@@ -968,7 +1090,8 @@ async function boot() {
  wireUploads();
  refreshAlerts();
  await sessionsPanel.refresh();
-  connect(urlSession ?? defaultSession(sessionsPanel.data));
+  if (urlSession) connect(urlSession, { existing: urlExisting });
+  else connect(defaultSession(sessionsPanel.data), { existing: true });
 }

 boot();
@@ -47,12 +47,12 @@ toast.info = (message, duration) => toast(message, 'info', duration);
 // ---------------------------------------------------------------- dialogs

 let openDialogs = 0;
-export const dialogOpen = () => openDialogs > 0 || document.getElementById('lt-cmd-overlay')?.classList.contains('is-open');
+export const dialogOpen = () => openDialogs > 0 || !!document.querySelector('.lt-cmd-overlay.is-open');

 // A .lt-modal dialog. `body` is a node; `actions` are { label, value, primary,
 // danger }. Resolves with the chosen action's value (or `submit()`'s value when
 // a form is submitted), or null when dismissed (✕, Esc, backdrop).
-export function openDialog({ title, body, actions = [], danger = false, size = '', onOpen, submit }) {
+export function openDialog({ title, body, actions = [], danger = false, size = '', className = '', onOpen, submit }) {
  return new Promise((resolve) => {
    const opener = document.activeElement;
    let done = false;
@@ -81,7 +81,7 @@ export function openDialog({ title, body, actions = [], danger = false, size = '
      if (button.type === 'submit') button.setAttribute('form', titleId);
    }
    form.id = titleId;
-    const overlay = el('div', { class: 'lt-modal-overlay is-open dd-dialog', role: 'dialog', 'aria-modal': 'true', 'aria-labelledby': `${titleId}-title` },
+    const overlay = el('div', { class: `lt-modal-overlay is-open dd-dialog${className ? ` ${className}` : ''}`, role: 'dialog', 'aria-modal': 'true', 'aria-labelledby': `${titleId}-title` },
      el('div', { class: `lt-modal${size ? ` lt-modal-${size}` : ''}` },
        el('div', { class: `lt-modal-header${danger ? ' lt-modal-header--danger' : ''}` },
          el('h2', { class: 'lt-modal-title', id: `${titleId}-title` }, title),
@@ -153,22 +153,26 @@ function pushRecent(id) {
 }

 // Commands: { id, label, group, icon?, hint?, kbd?, keywords?, run }. `getCommands`
-// is called on every open, so the list reflects the current sessions and state.
+// (may be async) is called on every open, so the list reflects the current state.
+// Options: id (DOM prefix), placeholder, search(commands, query) -> ranked list
+// (replaces the default word filter, recents and grouping; used by Go to file).
 export class CommandPalette {
-  constructor(getCommands) {
+  constructor(getCommands, options = {}) {
+    this.options = { id: 'lt-cmd', placeholder: 'Type a command or a session name…', ...options };
+    const id = this.options.id;
    this.getCommands = getCommands;
    this.commands = [];
    this.visible = [];
    this.selected = 0;
    this.opener = null;
    this.input = el('input', {
-      class: 'lt-cmd-input', type: 'text', placeholder: 'Type a command or a session name…',
-      autocomplete: 'off', spellcheck: 'false', 'aria-label': 'Command', role: 'combobox',
-      'aria-controls': 'dd-cmd-results', 'aria-expanded': 'true',
+      class: 'lt-cmd-input', type: 'text', placeholder: this.options.placeholder,
+      autocomplete: 'off', spellcheck: 'false', 'aria-label': this.options.placeholder, role: 'combobox',
+      'aria-controls': `${id}-results`, 'aria-expanded': 'true',
    });
-    this.results = el('div', { class: 'lt-cmd-results', id: 'dd-cmd-results', role: 'listbox' });
-    this.overlay = el('div', { class: 'lt-cmd-overlay', id: 'lt-cmd-overlay', role: 'dialog', 'aria-modal': 'true', 'aria-label': 'Command palette' },
-      el('div', { class: 'lt-cmd-palette', id: 'lt-cmd-palette' },
+    this.results = el('div', { class: 'lt-cmd-results', id: `${id}-results`, role: 'listbox' });
+    this.overlay = el('div', { class: 'lt-cmd-overlay', id: `${id}-overlay`, role: 'dialog', 'aria-modal': 'true', 'aria-label': this.options.placeholder },
+      el('div', { class: 'lt-cmd-palette', id: `${id}-palette` },
        el('div', { class: 'lt-cmd-input-wrap' }, el('span', { class: 'lt-cmd-prompt', 'aria-hidden': 'true' }, '>'), this.input),
        this.results,
        el('div', { class: 'lt-cmd-footer' },
@@ -187,13 +191,29 @@ export class CommandPalette {
    return this.overlay.classList.contains('is-open');
  }

-  open(query = '') {
+  async open(query = '') {
    this.opener = document.activeElement;
-    this.commands = this.getCommands();
    this.overlay.classList.add('is-open');
    this.input.value = query;
-    this.render();
    this.input.focus();
+    const pending = this.getCommands();
+    if (pending instanceof Promise) {
+      this.commands = [];
+      this.loading = true;
+      this.render();
+      try {
+        this.commands = await pending;
+      } catch (error) {
+        this.commands = [];
+        this.results.replaceChildren(el('div', { class: 'lt-cmd-empty' }, error.message));
+        return;
+      } finally {
+        this.loading = false;
+      }
+    } else {
+      this.commands = pending;
+    }
+    if (this.isOpen) this.render();
  }

  close({ restoreFocus = true } = {}) {
@@ -246,6 +266,15 @@ export class CommandPalette {
  }

  render() {
+    if (this.loading) {
+      this.visible = [];
+      this.results.replaceChildren(el('div', { class: 'lt-cmd-empty' }, 'Loading…'));
+      return;
+    }
+    if (this.options.search) {
+      this.renderList(this.options.search(this.commands, this.input.value.trim()));
+      return;
+    }
    const words = this.input.value.trim().toLowerCase().split(/\s+/).filter(Boolean);
    const matches = this.commands.filter((c) => {
      const text = `${c.label} ${c.group} ${c.keywords ?? ''} ${c.hint ?? ''}`.toLowerCase();
@@ -266,14 +295,29 @@ export class CommandPalette {
      this.results.replaceChildren(el('div', { class: 'lt-cmd-empty' }, `No command matches “${this.input.value.trim()}”`));
      return;
    }
+    this.renderGroups(groups);
+  }
+
+  // A ranked list without group headers (custom search).
+  renderList(list) {
+    this.visible = list;
+    this.selected = 0;
+    if (!list.length) {
+      this.results.replaceChildren(el('div', { class: 'lt-cmd-empty' }, this.input.value.trim() ? `Nothing matches “${this.input.value.trim()}”` : 'Nothing here'));
+      return;
+    }
+    this.renderGroups(new Map([['', list]]));
+  }
+
+  renderGroups(groups) {
    let index = 0;
    const nodes = [];
    for (const [group, commands] of groups) {
-      nodes.push(el('div', { class: 'lt-cmd-group-label', role: 'presentation' }, group));
+      if (group) nodes.push(el('div', { class: 'lt-cmd-group-label', role: 'presentation' }, group));
      for (const command of commands) {
        const i = index;
        nodes.push(el('div', {
-          class: 'lt-cmd-item', id: `dd-cmd-${i}`, role: 'option',
+          class: 'lt-cmd-item', id: `${this.options.id}-item-${i}`, role: 'option',
          onclick: () => this.run(command),
          onmousemove: () => {
            if (this.selected !== i) {
@@ -699,3 +699,251 @@ html[data-theme="light"] .lt-notif-dot { box-shadow: none; }
  .dd-panels-icon { display: inline; font-size: 1rem; }
  .dd-inbox-panel { position: fixed; top: calc(var(--header-height) + 4px); right: 8px; left: 8px; width: auto; }
 }
+
+/* ---- files pane (devdesk#19, #37): explorer + tabs + editor ---------------------- */
+.dd-files {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  flex: 0 0 var(--dd-files-w, 52%);
+  min-width: 0;
+  margin: 0;
+  background: var(--bg-terminal);
+  --dd-explorer-w: 240px;
+}
+.dd-files[hidden] { display: none; }
+body.dd-resizing { cursor: col-resize; user-select: none; }
+body.dd-resizing .dd-terminal,
+body.dd-resizing .dd-md-frame { pointer-events: none; }
+.dd-files-resizer {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: calc(-1 * var(--dd-gap) - 2px);
+  width: calc(var(--dd-gap) + 6px);
+  cursor: col-resize;
+  z-index: 3;
+}
+.dd-files-resizer:hover,
+.dd-files-resizer:focus-visible,
+body.dd-resizing .dd-files-resizer { background: linear-gradient(90deg, transparent 40%, var(--accent-cyan) 40%, var(--accent-cyan) 60%, transparent 60%); outline: none; }
+#files-toggle[aria-expanded="true"] { color: var(--accent-orange); border-color: var(--accent-orange-border); }
+
+/* head: explorer toggle | tabs | actions */
+.dd-files-head { display: flex; align-items: stretch; gap: 2px; min-height: 34px; padding: 0 4px; border-bottom: 1px solid var(--border-dim); background: var(--bg-secondary); }
+.dd-files-head .dd-icon-btn { align-self: center; }
+.dd-files-actions { display: flex; align-items: center; gap: 2px; margin-left: auto; }
+.dd-tabs { display: flex; flex: 1; min-width: 0; overflow-x: auto; scrollbar-width: thin; }
+.dd-tab {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  max-width: 220px;
+  padding: 0 6px 0 10px;
+  border-right: 1px solid var(--border-dim);
+  border-top: 2px solid transparent;
+  color: var(--text-muted);
+  font-family: var(--font-mono);
+  font-size: 0.74rem;
+  white-space: nowrap;
+  cursor: pointer;
+  user-select: none;
+}
+.dd-tab:hover { color: var(--text-primary); background: var(--bg-tertiary); }
+.dd-tab.is-active { color: var(--text-primary); background: var(--bg-terminal); border-top-color: var(--accent-orange); }
+.dd-tab.is-preview .dd-tab-name { font-style: italic; }
+.dd-tab-name { overflow: hidden; text-overflow: ellipsis; }
+.dd-tab-tag { padding: 0 4px; border: 1px solid var(--border-color); color: var(--text-muted); font-size: 0.6rem; }
+.dd-tab-close { width: 18px; height: 18px; padding: 0; border: 0; background: none; color: inherit; opacity: 0; font-size: 0.9rem; line-height: 1; cursor: pointer; }
+.dd-tab:hover .dd-tab-close,
+.dd-tab.is-active .dd-tab-close,
+.dd-tab-close:focus-visible { opacity: 0.7; }
+.dd-tab-close:hover { opacity: 1; color: var(--accent-red); }
+.dd-tab.git-amber .dd-tab-name { color: var(--accent-amber); }
+.dd-tab.git-green .dd-tab-name { color: var(--accent-green); }
+.dd-tab.git-red .dd-tab-name { color: var(--accent-red); text-decoration: line-through; }
+
+/* main: explorer column | editor */
+.dd-files-main { position: relative; display: flex; flex: 1; min-height: 0; }
+.dd-explorer { display: flex; flex-direction: column; flex: 0 0 var(--dd-explorer-w); min-width: 0; border-right: 1px solid var(--border-dim); background: var(--bg-secondary); }
+.dd-files.explorer-hidden .dd-explorer,
+.dd-files.explorer-hidden .dd-explorer-resizer,
+.dd-files.is-narrow .dd-explorer-resizer { display: none; }
+.dd-explorer-resizer { flex: 0 0 4px; margin-left: -2px; margin-right: -2px; cursor: col-resize; z-index: 2; }
+.dd-explorer-resizer:hover { background: var(--accent-cyan); }
+.dd-explorer-views { display: flex; border-bottom: 1px solid var(--border-dim); }
+.dd-explorer-views button {
+  flex: 1;
+  padding: 6px 4px 5px;
+  border: 0;
+  border-bottom: 2px solid transparent;
+  background: none;
+  color: var(--text-muted);
+  font-family: var(--font-mono);
+  font-size: 0.64rem;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+  cursor: pointer;
+}
+.dd-explorer-views button:hover { color: var(--text-primary); }
+.dd-explorer-views button[aria-selected="true"] { color: var(--accent-orange); border-bottom-color: var(--accent-orange); }
+.dd-files-count:not(:empty) { margin-left: 3px; padding: 0 5px; border-radius: 8px; background: var(--accent-amber-dim); color: var(--accent-amber); font-size: 0.6rem; }
+.dd-explorer-body { flex: 1; min-height: 0; overflow: auto; padding: 4px 0 12px; outline: none; }
+
+.dd-tree-row {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  min-height: 24px;
+  padding-right: 8px;
+  color: var(--text-primary);
+  font-family: var(--font-mono);
+  font-size: 0.76rem;
+  white-space: nowrap;
+  cursor: pointer;
+  user-select: none;
+}
+.dd-tree-row:hover { background: var(--bg-tertiary); }
+.dd-tree-row:focus-visible { outline: 1px solid var(--accent-cyan); outline-offset: -1px; }
+.dd-tree-row.is-active { background: var(--accent-cyan-dim); box-shadow: inset 2px 0 0 var(--accent-cyan); }
+.dd-tree-row.is-ignored { opacity: 0.5; }
+.dd-tree-row.is-note { color: var(--text-muted); font-size: 0.7rem; cursor: default; }
+.dd-tree-row.is-disabled { opacity: 0.5; cursor: default; }
+.dd-tree-name { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; }
+.dd-tree-row.git-amber .dd-tree-name { color: var(--accent-amber); }
+.dd-tree-row.git-green .dd-tree-name { color: var(--accent-green); }
+.dd-tree-row.git-red .dd-tree-name { color: var(--accent-red); text-decoration: line-through; }
+.dd-tree-row.git-cyan .dd-tree-name { color: var(--accent-cyan); }
+.dd-tree-row.git-dirty > .dd-tree-name { color: var(--accent-amber); }
+.dd-dirty-dot { flex: 0 0 6px; height: 6px; border-radius: 50%; background: var(--accent-amber); }
+.dd-change-dir { color: var(--text-muted); font-size: 0.66rem; }
+.dd-changes-head { padding: 6px 10px; color: var(--text-muted); font-size: 0.68rem; border-bottom: 1px solid var(--border-dim); }
+
+/* file-type badges */
+.dd-ficon {
+  flex: 0 0 18px;
+  font-family: var(--font-mono);
+  font-size: 0.56rem;
+  font-weight: 700;
+  letter-spacing: -0.04em;
+  text-align: center;
+  line-height: 1;
+}
+.dd-ficon.tone-dir { color: var(--text-muted); font-size: 0.7rem; }
+.dd-ficon.tone-cyan { color: var(--accent-cyan); }
+.dd-ficon.tone-amber { color: var(--accent-amber); }
+.dd-ficon.tone-blue { color: #5b9cff; }
+.dd-ficon.tone-green { color: var(--accent-green); }
+.dd-ficon.tone-purple { color: var(--accent-purple); }
+.dd-ficon.tone-orange { color: var(--accent-orange); }
+.dd-ficon.tone-muted { color: var(--text-muted); }
+html[data-theme="light"] .dd-ficon.tone-blue { color: #1f4fbf; }
+
+.dd-file-status { flex: 0 0 1.1em; font-weight: 700; text-align: center; font-size: 0.7rem; }
+.dd-file-status.is-amber { color: var(--accent-amber); }
+.dd-file-status.is-green { color: var(--accent-green); }
+.dd-file-status.is-red { color: var(--accent-red); }
+.dd-file-status.is-cyan { color: var(--accent-cyan); }
+.dd-claude-chip { padding: 0 4px; border: 1px solid var(--accent-orange-border); color: var(--accent-orange); font-size: 0.58rem; font-weight: 700; }
+.dd-add { color: var(--accent-green); font-size: 0.66rem; }
+.dd-del { color: var(--accent-red); font-size: 0.66rem; }
+.dd-files-msg { padding: 14px; color: var(--text-muted); font-size: 0.76rem; line-height: 1.5; }
+.dd-files-msg.is-error { color: var(--accent-red); }
+
+/* editor area */
+.dd-editor-area { position: relative; display: flex; flex: 1; min-width: 0; flex-direction: column; }
+.dd-tab-view { display: flex; flex: 1; min-height: 0; flex-direction: column; }
+.dd-tab-view[hidden] { display: none; }
+.dd-viewer-bar { display: flex; align-items: center; gap: 8px; min-height: 30px; padding: 3px 8px; border-bottom: 1px solid var(--border-dim); }
+.dd-viewer-where { flex: 1; min-width: 0; overflow: hidden; font-size: 0.7rem; text-overflow: ellipsis; white-space: nowrap; }
+.dd-viewer-path { color: var(--text-secondary); }
+.dd-viewer-meta { color: var(--text-muted); font-size: 0.66rem; transition: color 0.6s; }
+.dd-viewer-meta.is-flash { color: var(--accent-amber); }
+.dd-viewer-actions { display: flex; flex: 0 0 auto; gap: 4px; }
+.dd-viewer-btn {
+  padding: 2px 8px;
+  border: 1px solid var(--border-color);
+  background: none;
+  color: var(--accent-cyan);
+  font-family: var(--font-mono);
+  font-size: 0.68rem;
+  white-space: nowrap;
+  cursor: pointer;
+}
+.dd-viewer-btn:hover { border-color: var(--accent-cyan); background: var(--accent-cyan-dim); }
+.dd-viewer-content { display: flex; flex: 1; min-height: 0; flex-direction: column; overflow: hidden; }
+.dd-viewer-content > .cm-editor { flex: 1; min-height: 0; }
+.dd-viewer-content .cm-editor.cm-focused { outline: none; }
+.dd-viewer-content.is-image {
+  align-items: center;
+  justify-content: center;
+  overflow: auto;
+  padding: 12px;
+  background: repeating-conic-gradient(var(--bg-secondary) 0 25%, var(--bg-terminal) 0 50%) 0 0 / 20px 20px;
+}
+.dd-viewer-content.is-image img { max-width: 100%; height: auto; box-shadow: 0 2px 12px rgba(0, 0, 0, 0.3); }
+.dd-md-frame { flex: 1; width: 100%; border: 0; background: var(--bg-terminal); }
+.dd-plain { flex: 1; margin: 0; padding: 10px; overflow: auto; font-size: 0.76rem; white-space: pre; }
+
+/* empty editor */
+.dd-editor-empty { display: flex; flex: 1; flex-direction: column; gap: 14px; padding: 28px 24px; overflow: auto; }
+.dd-editor-empty[hidden] { display: none; }
+.dd-empty-title { color: var(--text-secondary); font-size: 0.82rem; }
+.dd-empty-actions { display: flex; flex-wrap: wrap; gap: 6px; }
+.dd-empty-actions .dd-viewer-btn { padding: 5px 12px; font-size: 0.72rem; }
+.dd-empty-label { margin-bottom: 4px; color: var(--accent-orange); font-size: 0.62rem; letter-spacing: 0.12em; text-transform: uppercase; }
+.dd-recent { display: flex; align-items: center; gap: 6px; width: 100%; padding: 3px 4px; border: 0; background: none; color: var(--accent-cyan); font-family: var(--font-mono); font-size: 0.76rem; text-align: left; cursor: pointer; }
+.dd-recent:hover { background: var(--accent-cyan-dim); }
+.dd-recent-name { white-space: nowrap; }
+.dd-empty-hint { color: var(--text-muted); font-size: 0.68rem; }
+
+/* Narrow pane (phone, or dragged small): the explorer slides over the editor
+   and closes when a file opens; ☰ brings it back. */
+.dd-files.is-narrow .dd-explorer {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  z-index: 4;
+  width: min(300px, 85%);
+  box-shadow: 8px 0 24px rgba(0, 0, 0, 0.45);
+}
+html[data-theme="light"] .dd-files.is-narrow .dd-explorer { box-shadow: 8px 0 24px rgba(50, 80, 130, 0.25); }
+
+@media (max-width: 1099px) {
+  /* Narrow window: the pane covers the terminal instead of squeezing it
+     (squeezing would resize tmux for every client). */
+  .dd-files { position: absolute; inset: var(--dd-gap); z-index: 18; flex: none; }
+  .dd-files-resizer { display: none; }
+}
+@media (max-width: 719px) {
+  .dd-cmd-btn { display: none; }
+  .dd-tab { max-width: 160px; }
+}
+@media (pointer: coarse) {
+  .dd-tree-row { min-height: 34px; }
+  .dd-tab-close { opacity: 0.7; width: 28px; height: 28px; }
+}
+
+/* ---- editing (devdesk#20) ------------------------------------------------------------- */
+.dd-tab-view:not(.is-dirty) .dd-dirty-only { display: none; }
+.dd-unsaved { color: var(--accent-amber); }
+.dd-tab.is-dirty .dd-tab-close { opacity: 1; color: var(--accent-amber); }
+.dd-tab.is-dirty .dd-tab-close:hover { color: var(--accent-red); }
+.dd-viewer-btn.is-primary { border-color: var(--accent-orange); color: var(--accent-orange); }
+.dd-viewer-btn.is-primary:hover { background: var(--accent-orange-dim); }
+.dd-viewer-banner {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 6px 10px;
+  padding: 5px 10px;
+  border-bottom: 1px solid var(--accent-amber-dim);
+  background: var(--accent-amber-dim);
+  color: var(--accent-amber);
+  font-size: 0.72rem;
+}
+.dd-dialog.is-wide .lt-modal { width: min(1100px, 94vw); max-height: 88vh; }
+.dd-dialog.is-wide .lt-modal-body { padding: 0; }
+.dd-compare { display: flex; height: min(64vh, 640px); }
+.dd-compare > .cm-editor { flex: 1; min-width: 0; }
Author	SHA1	Message	Date
jaredandClaude Opus 5.5	66321f4748	feat: v0.8.0 edit and save files with conflict detection build-deb / Lint, test, package (push) Successful in 1m57s Details build-deb / Deploy to CT 126 (push) Successful in 3s Details build-deb / Notify on failure (push) Skipped Details - devdesk attach --fs-write SESSION PATH BYTES BASESHA\|new: streamed like uploads, temp file in the same folder, sha re-check (conflict reply instead of overwriting), mode/owner kept, atomic mv; new files with folders, never outside the session folder or through a symlink out of it. - Editor: editable CodeMirror for UTF-8 text, dirty tracking, Ctrl+S, Save/Revert, conflict dialog with a disk-vs-yours diff, changed-on-disk banner, drafts in localStorage (flushed on pagehide), close/leave guards, New file. - Upload streaming factored into streamIn(), shared by uploads and saves. Closes #20 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-10-10 20:10:45 -04:00
jaredandClaude Opus 5.5	927920c162	fix: old links never re-create ended sessions build-deb / Lint, test, package (push) Successful in 1m56s Details build-deb / Deploy to CT 126 (push) Successful in 24s Details build-deb / Notify on failure (push) Skipped Details Inbox entries, the switcher, palette switches, the attention chip and Matrix links (?arg=NAME&existing=1) attach with --existing; an ended session gets an explanation and an explicit "Start again". Inbox entries for ended sessions can't resurrect them; entries expire after 7 days. Closes #38 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-10-10 19:57:52 -04:00
jaredandClaude Opus 5.5	dee1843986	fix: go to file in big non-git folders; linear reply handling build-deb / Lint, test, package (push) Successful in 3m0s Details build-deb / Deploy to CT 126 (push) Successful in 3s Details build-deb / Notify on failure (push) Skipped Details - find/git producers piped into head tolerate SIGPIPE, so hitting a cap no longer fails the command (and lets ttyd truncate its reply). - fs-find outside git skips build/cache folders and caps at 10000. - runCommand checks completion on the stream's tail instead of re-decoding the whole reply on every frame. Refs #37 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-10-08 01:50:50 -04:00
jaredandClaude Opus 5.5	e345bf4640	feat: files pane like VS Code: tree, tabs, go to file build-deb / Lint, test, package (push) Successful in 2m28s Details build-deb / Deploy to CT 126 (push) Successful in 3s Details build-deb / Notify on failure (push) Skipped Details - Explorer tree with inline expand/collapse and keyboard navigation, git colours, change dots, dimmed gitignored entries (fs-list now flags them), file-type badges, resizable explorer. - Editor tabs: preview tab semantics, instant switching with scroll kept, in-place reload when Claude changes an open file. - Go to file: devdesk attach --fs-find (git ls-files or capped find) and a fuzzy-ranked palette (CommandPalette gained custom search/async lists). - Per-session memory of folders and tabs; empty state with recents. Closes #37 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-10-08 01:40:47 -04:00
jaredandClaude Opus 5.5	73f8525db2	feat: v0.7.0 files pane: browse, preview, diff, Claude's edits build-deb / Lint, test, package (push) Successful in 2m38s Details build-deb / Deploy to CT 126 (push) Successful in 5s Details build-deb / Notify on failure (push) Skipped Details - devdesk attach --fs-list/--fs-read/--git-status/--git-show/--asset (libexec/devdesk-files.sh), confined to the session folder. - The state hook records files Claude edits (Edit/Write/MultiEdit/ NotebookEdit) for the Changes tab's "C" badge; rename/end carry it. - Files pane: folders, CodeMirror read-only view, sanitized markdown preview in a sandboxed iframe with inlined relative images, images, Changes tab with line counts and diff against HEAD, "→ Claude" @path, resizable split. - The editor bundle ships as /usr/share/devdesk/assets/editor.js, is fetched over ttyd on first use, verified against the page's SHA-256 and cached in IndexedDB. - Fix: the state hook's field split collapsed empty fields. Closes #19 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-10-08 01:16:37 -04:00