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>

etc/env

@@ -33,5 +33,14 @@ DEVDESK_GRAFANA_TOKEN_FILE=/etc/devdesk/grafana-token
 CLAUDE_BIN=/root/.local/bin/claude
 CLAUDE_ARGS=
 
+# Where DevDesk is reached in a browser; used for links in Matrix notifications.
+DEVDESK_PUBLIC_URL=https://dev.lotusguild.org
+
+# "Claude needs you" in Matrix when a session waits and no tab or SSH client is
+# attached: put a hookshot webhook URL in this file (mode 600). No file = off.
+# DEVDESK_MATRIX_DELAY: seconds the wait must last before posting.
+DEVDESK_MATRIX_WEBHOOK_FILE=/etc/devdesk/matrix-webhook
+DEVDESK_MATRIX_DELAY=30
+
 # 1 = also enable Remote Control so sessions can be continued from the Claude app.
 DEVDESK_REMOTE_CONTROL=0