feat(web): weekly automatic updates with health check and rollback (#581)

* feat(web): weekly automatic updates with health check and rollback

A General-tab toggle (off by default) checks for and installs LEDMatrix and
plugin updates once a week, overnight in the configured timezone.

- Pre-update checks skip (and report) instead of forcing: local edits or
  commits, merge/live rebase, no upstream, low disk, missing health check, or
  a version that was already rolled back. An abandoned rebase (HEAD back on a
  branch) is cleared, since it would otherwise block every pull.
- The pull reuses the Update Code path (now perform_core_update(), which
  reports dependency install failures as data).
- ledmatrix-update-verify.service, started via a .path unit from a request
  file, restarts the services from its own cgroup, requires them to come up
  and stay up, and otherwise resets to the previous commit and reinstalls the
  previous requirements. It runs a copy of the checker taken before the pull.
- No SSH needed: switching the toggle on restarts the display service, which
  (as root) installs the two units from the repo templates for the web user.
  first_time_install.sh installs them too and takes --enable-auto-update /
  LEDMATRIX_AUTO_UPDATE (passed through by one-shot-install.sh).
- Plugins update after the code passes its check; failures, blocks and
  rollbacks raise an Overview banner and show under the toggle.

Tested end to end on a Pi: web-UI setup, a good update, a broken web service
and a broken display (both rolled back), a blocked local edit, and an
abandoned rebase found on the device.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* chore(auto-update): address static-analysis findings

- Replace the subprocess.CompletedProcess the verifier fabricated for a
  command that could not start with a plain namedtuple; nothing is executed
  there, but the scanner flags any CompletedProcess built from variables.
- Mark the subprocess imports with the repo's standard B404 annotation (all
  calls are list-form argv, no shell).
- Mark the rollback-failed message as not SQL (B608 matched its wording).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(auto-update): CI failures on Linux

- Keep the setup result when chown fails. CI runs as a non-root user, where
  chown to the web user raises; that discarded the result file, so the
  General tab would never learn whether setup worked. Regression test added.
- Register the two new /api/v3/system/auto-update routes in the URL map
  snapshot.
- Use utility classes app.css defines (space-y-1, hover:text-red-600).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(auto-update): address review feedback

- Health check: a failed restart command no longer lets the check run
  against the still-running old process; it counts as a failure (and after a
  rollback, as a failed rollback). An unreadable restart count is never
  treated as stable, since a crash loop looks healthy between attempts.
- Installer writes the auto_update setting to a temp file and swaps it in,
  keeping mode and owner, so a running config watcher never reads a
  truncated config.json.
- Verify unit quotes its command-line paths (install folders with spaces);
  setup refuses folder names systemd would reinterpret (%, quotes,
  backslashes, control characters) and says so on the General tab.
- The auto-update status route no longer returns exception text.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(auto-update): keep error detail in the status route's 500

test_web_error_detail requires every 5xx handler to log the traceback and
return describe_exception(e), which redacts credentials, so failures are
diagnosable from the web UI. Dropping it for CodeQL broke that policy.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(auto-update): dismiss route rejects non-object JSON with 400

A JSON array or scalar body made `.get('alert_id')` raise, returning 500.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(auto-update): let the app-wide handler answer status-route errors

CodeQL (py/stack-trace-exposure, #709) flagged the route's own except,
which returned describe_exception(e). web_interface/app.py's error handler
already logs the traceback and returns the same redacted detail for any
unhandled exception, so the local copy is removed: same response, no new
exception-to-response flow, and test_web_error_detail's policy still holds.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

web_interface/app.py

@@ -1047,8 +1047,36 @@ def check_health_monitor():
             _reconciliation_started = True
             _threading.Thread(target=_run_startup_reconciliation, daemon=True).start()
 
+_auto_updater = None
+
+
+def start_auto_update_scheduler():
+    """Start the weekly auto-update thread (web_interface/auto_update.py).
+
+    Called by the launchers, not at import: tests and dev tools import this
+    module, and none of them should ever git pull. Idle unless
+    auto_update.enabled is set, so it is safe to always start.
+    """
+    global _auto_updater
+    if _auto_updater is not None:
+        return _auto_updater
+    from web_interface.auto_update import AutoUpdater
+    from web_interface.blueprints.api_v3.system import perform_core_update
+    _auto_updater = AutoUpdater(
+        config_manager=config_manager,
+        core_update=perform_core_update,
+        store_manager=plugin_store_manager,
+        plugin_manager=plugin_manager,
+        schema_manager=schema_manager,
+        operation_history=operation_history,
+    )
+    _auto_updater.start()
+    return _auto_updater
+
+
 if __name__ == '__main__':
     import os as _os
+    start_auto_update_scheduler()
     # threaded=True is Flask's default since 1.0 but stated explicitly so that
     # long-lived /api/v3/stream/* SSE connections don't starve other requests.
     # Debug mode is off by default; opt in with FLASK_DEBUG=1 in the environment.