feat: free-form sessions, rename/end from the panel, live Claude Context (0.2.0)

- Sessions no longer need a project folder: any name works and starts in
  DEVDESK_DEFAULT_DIR unless it matches a project; `devdesk new NAME [PROJECT]`.
- Rename (✎) and end/forget (×) sessions from the Sessions panel, plus
  `devdesk rename`. The browser runs them as `devdesk attach --new|--rename|--end`
  through ttyd. Renames keep the running Claude and its recorded conversation:
  the hook, the run-wrapper and the statusline ask tmux for the current name.
- Claude Context panel is live: devdesk-statusline snapshots model,
  context-window use, cost and edits per session, which --list reports;
  Claude's footer gets a one-line summary. The panel now sits under Sessions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libexec/devdesk-lib.sh

@@ -11,6 +11,7 @@ if [ -r "$DEVDESK_ENV" ]; then
 fi
 
 : "${DEVDESK_PROJECTS_ROOT:=/root/code}"
+: "${DEVDESK_DEFAULT_DIR:=$DEVDESK_PROJECTS_ROOT}"
 : "${DEVDESK_DEFAULT_SESSION:=main}"
 : "${DEVDESK_SOCKET:=/run/devdesk/tmux.sock}"
 : "${DEVDESK_STATE_DIR:=/var/lib/devdesk}"
@@ -19,6 +20,7 @@ fi
 : "${DEVDESK_TMUX_UNIT:=devdesk-tmux.service}"
 
 DEVDESK_REGISTRY="$DEVDESK_STATE_DIR/registry.json"
+DEVDESK_CONTEXT_DIR="$DEVDESK_STATE_DIR/context"
 DEVDESK_NAME_RE='^[A-Za-z0-9][A-Za-z0-9_-]{0,63}$'
 
 dd_die() {
@@ -99,29 +101,30 @@ dd_registry_set_claude() {
 
 dd_registry_remove() {
     dd_registry_update 'del(.sessions[$n])' --arg n "$1"
+    rm -f "$DEVDESK_CONTEXT_DIR/$1.json"
 }
 
-# Session name -> absolute project directory (must resolve inside the projects root).
-dd_resolve_dir() {
+dd_registry_rename() {
+    dd_registry_update 'if .sessions[$old] then .sessions[$new] = .sessions[$old] | del(.sessions[$old]) else . end' \
+        --arg old "$1" --arg new "$2"
+    if [ -f "$DEVDESK_CONTEXT_DIR/$1.json" ]; then
+        mv -f "$DEVDESK_CONTEXT_DIR/$1.json" "$DEVDESK_CONTEXT_DIR/$2.json"
+    fi
+}
+
+# Project name (directory or its slug) -> absolute directory inside the projects root.
+dd_project_dir() {
     local name=$1 dir="" d root
-    if [ "$name" = "$DEVDESK_DEFAULT_SESSION" ]; then
-        dir=$DEVDESK_PROJECTS_ROOT
+    if [ -d "$DEVDESK_PROJECTS_ROOT/$name" ]; then
+        dir="$DEVDESK_PROJECTS_ROOT/$name"
     else
-        dir=$(dd_registry_get "$name" dir)
-        if [ -z "$dir" ] || [ ! -d "$dir" ]; then
-            dir=""
-            if [ -d "$DEVDESK_PROJECTS_ROOT/$name" ]; then
-                dir="$DEVDESK_PROJECTS_ROOT/$name"
-            else
-                for d in "$DEVDESK_PROJECTS_ROOT"/*/; do
-                    d=${d%/}
-                    if [ "$(dd_slugify "${d##*/}")" = "$name" ]; then
-                        dir=$d
-                        break
-                    fi
-                done
+        for d in "$DEVDESK_PROJECTS_ROOT"/*/; do
+            d=${d%/}
+            if [ "$(dd_slugify "${d##*/}")" = "$name" ]; then
+                dir=$d
+                break
             fi
-        fi
+        done
     fi
     [ -n "$dir" ] || return 1
     dir=$(realpath -e -- "$dir" 2>/dev/null) || return 1
@@ -132,6 +135,30 @@ dd_resolve_dir() {
     esac
 }
 
+# Session name -> working directory. Sessions don't need a project: the
+# registry wins, then a project of the same name, then DEVDESK_DEFAULT_DIR.
+dd_resolve_dir() {
+    local name=$1 dir
+    dir=$(dd_registry_get "$name" dir)
+    if [ -n "$dir" ] && [ -d "$dir" ]; then
+        printf '%s\n' "$dir"
+    elif [ "$name" != "$DEVDESK_DEFAULT_SESSION" ] && dir=$(dd_project_dir "$name"); then
+        printf '%s\n' "$dir"
+    else
+        realpath -e -- "$DEVDESK_DEFAULT_DIR" 2>/dev/null || printf '%s\n' "$HOME"
+    fi
+}
+
+# Name of the DevDesk session this process runs in. Asks tmux, so it stays
+# right after a rename; falls back to the DEVDESK_SESSION set at creation.
+dd_current_session() {
+    local name=""
+    if [ -n "${TMUX:-}" ] && [ -n "${TMUX_PANE:-}" ]; then
+        name=$(tmux display-message -p -t "$TMUX_PANE" '#S' 2>/dev/null)
+    fi
+    printf '%s\n' "${name:-${DEVDESK_SESSION:-}}"
+}
+
 # Arguments for `tmux new-session` that create session NAME in DIR running Claude.
 dd_new_session_args() {
     printf '%s\0' -s "$1" -c "$2" -n claude -e "DEVDESK_SESSION=$1" "$DEVDESK_LIBEXEC/devdesk-claude-run"