feat: v0.5.0 header, switcher, phone key bar, shared polling, Matrix "needs you"

- Header: no SSO chip ("Sign in again" only on expiry), state dot on the
  session chip, LIVE as a dot, ⋯ menu for text size/notifications/fullscreen,
  Panels badge for waiting sessions and alerts.
- Session switcher on the chip; bare URL reattaches the last session; + New
  opens the panel form with project folders.
- Notifications when other sessions start waiting; alerts polled with the
  panels closed; one tab polls for all tabs over BroadcastChannel.
- Sidebar: context bar per session instead of the Context panel; compact
  Repo/CI with "Ask Claude to fix CI"; legible labels.
- Phone: key bar, drawer with backdrop, visualViewport-aware layout, DOM
  renderer on touch, compact connection dot.
- devdesk-notify-matrix: one Matrix message per wait that lasts
  DEVDESK_MATRIX_DELAY seconds with nobody attached.

Closes #8
Closes #13
Closes #14
Closes #15
Closes #16
Closes #17
Closes #28

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

libexec/devdesk-notify-matrix

@@ -0,0 +1,41 @@
+#!/bin/bash
+# devdesk-notify-matrix SESSION SINCE
+#
+# Started (detached) by devdesk-state-hook when a session starts waiting on you.
+# After DEVDESK_MATRIX_DELAY seconds, if that same wait is still on and nobody is
+# attached to the session (no browser tab, no SSH client), post one "Claude needs
+# you" message to the hookshot webhook in DEVDESK_MATRIX_WEBHOOK_FILE (devdesk#28).
+set -euo pipefail
+
+# shellcheck source=libexec/devdesk-lib.sh
+. "${DEVDESK_LIBEXEC:-/usr/lib/devdesk}/devdesk-lib.sh"
+
+session=${1:-}
+since=${2:-}
+dd_valid_name "$session" || exit 0
+[[ $since =~ ^[0-9]+$ ]] || exit 0
+[ -r "$DEVDESK_MATRIX_WEBHOOK_FILE" ] || exit 0
+
+sleep "$DEVDESK_MATRIX_DELAY"
+
+state_file="$DEVDESK_STATUS_DIR/$session.json"
+# Still the same wait? (Answering it moves the state on; a new wait has its own notifier.)
+[ "$(jq -rM '"\(.state) \(.since)"' "$state_file" 2>/dev/null)" = "waiting $since" ] || exit 0
+# Anyone looking at it already?
+attached=$(dd_tmux list-sessions -F '#{session_name} #{session_attached}' 2>/dev/null |
+    awk -v s="$session" '$1 == s { print $2 }')
+[ "${attached:-0}" = 0 ] || exit 0
+
+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=$session"
+body=$(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 " — " + $u end))}')
+
+# The webhook URL is a secret (anyone holding it can post to the room): pass it
+# to curl on stdin, never on the command line.
+# shellcheck disable=SC1003 # tr deletes whitespace, quotes and backslashes from the URL
+webhook=$(tr -d '[:space:]"\\' <"$DEVDESK_MATRIX_WEBHOOK_FILE")
+printf 'url = "%s"\n' "$webhook" |
+    curl -fsS --max-time 10 --retry 2 -K - -H 'Content-Type: application/json' --data-binary "$body" >/dev/null