panel: redesign web UI and make syncing responsive

Web UI (panel/frontend/index.html) rewritten:
- Cards update in place from a single /status poll instead of being rebuilt
  on every action, so open tabs, unsaved compose/route edits, logs and the
  file browser position survive refreshes. Polling speeds up while an
  operation runs and pauses in background tabs; a header indicator shows
  when the panel last synced and detects an expired Authelia session.
- New-app dialog (starter / compose / git), suggested port and domain,
  proper confirm dialogs (the old "OK = keep volumes" remove prompt is gone),
  toasts, an activity drawer with operation output, overflow menu, search,
  status filters, keyboard shortcuts, deep links, dark mode and mobile layout.
- Tabs: overview (containers + routes), compose editor (dirty tracking,
  Ctrl+S), logs with follow, validated routes editor, file browser with
  drag-and-drop upload, backups, and a git source tab (deployed commit,
  check for updates, sync & deploy).

API (panel/panel-api.py):
- ThreadingHTTPServer so a long deploy no longer blocks every other request.
- Per-app operation lock; concurrent writes to a busy app return 409.
- GET /status: all apps, routes and container status in one request
  (statuses gathered in parallel); status reports running/partial/stopped.
- Git sync is fetch + hard reset instead of pull-or-reclone, keeps the stored
  token, reports before/after commits; GET /apps/<name>/repo[?fetch=1].
- Any http(s) git host (e.g. Forgejo), default branch detection, git
  timeouts, no credential prompts, tokens redacted from errors, and manifest
  values validated before being written into the bash-sourced manifest.

panelctl:
- flock around routes.caddy rewrites (util-linux added to the service path).
- deploy returns compose output so failures are visible in the UI.
- inspect-volumes no longer fails for apps without named podman volumes,
  which broke the file browser.

Docs: README/API.md updated; fixed outdated panelctl init examples.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UbWSNkXxZhYf7eqHTyx3Bf

README.md

@@ -22,14 +22,19 @@ All app routes are written to a single `routes/routes.caddy` file that Caddy imp
 ## Quick workflow
 
 ```bash
-# Create a new app (single domain)
-panelctl init whoami whoami.srazka.com 18080 true
+# Routes are "domain|upstream[|path]" entries, comma-separated.
 
-# Create with multiple domains
-panelctl init myapp "app.srazka.com,www.srazka.com" 18081 true
+# Create a new app (single route, protected by Authelia)
+panelctl init whoami "whoami.srazka.com|127.0.0.1:18080" true
+
+# Create with multiple routes (different ports, optional path)
+panelctl init myapp "app.srazka.com|127.0.0.1:18081,api.srazka.com|127.0.0.1:18082|/api/*" true
 
 # Create with wildcard domain (requires DNS challenge in Caddy)
-panelctl init wild "*.srazka.com" 18082 false
+panelctl init wild "*.srazka.com|127.0.0.1:18083" false
+
+# Change routes later (Caddy reloads automatically)
+panelctl set-routes whoami "whoami.srazka.com|127.0.0.1:18080,who.srazka.com|127.0.0.1:18080"
 
 # Deploy (compose up + caddy reload)
 panelctl deploy whoami
@@ -91,9 +96,34 @@ panelctl remove whoami
 
 ### Web UI features
 
-- Create apps with multiple domains and wildcard support
-- Live container status indicators (auto-refreshes)
-- Deploy, restart, stop, remove from the UI
-- Inline compose editor with save, validate, and save+deploy
-- Log viewer with configurable tail length
-- Volume backup management: create, list, download, restore
+- Live status: one `/status` poll every few seconds (faster while something is
+  running, paused when the tab is hidden) updates cards in place, so open tabs,
+  unsaved edits and scroll positions are never lost. The header shows when the
+  panel last synced and warns when the Authelia session has expired.
+- Per-app status (running / partial / stopped), container list, and a busy
+  indicator that is shared between browsers while an operation runs.
+- New-app dialog: starter container, pasted compose file or git repository;
+  suggests the next free port and a domain based on the app name.
+- Compose editor with unsaved-changes tracking, Ctrl+S, save & deploy, validate.
+- Logs with follow mode, routes editor with validation, file browser with
+  drag-and-drop upload, backups with restore (and optional redeploy).
+- Git source tab: deployed commit, "check for updates", and sync & deploy.
+- Activity drawer with the output of every operation (e.g. why a deploy failed).
+- Keyboard: `/` search, `N` new app, `Esc` closes menus. Deep links like
+  `#/whoami/logs` open an app on a specific tab.
+
+### Git-backed apps
+
+Apps created from a repository (GitHub, Forgejo/Gitea or any https git host)
+are cloned to `stacks/<app>/repo`. **Sync** fetches the configured branch and
+hard-resets the checkout to it before redeploying, so the repository is the
+source of truth: compose edits made in the panel are discarded on the next sync
+(the UI warns about this). An access token for a private repository is stored in
+the clone's `.git/config`; use a read-only token.
+
+### Concurrency
+
+`panel-api` handles requests concurrently, so a long deploy never blocks status
+or logs. Mutating operations are serialised per app — a second operation on a
+busy app gets HTTP 409 — and `panelctl` takes a `flock` on the shared routes
+file while rewriting it.