fix(web): address CodeRabbit review — validation, a11y, perf, and privacy fixes

Verified each finding against current code. Fixed:

- api_v3: plugin_rotation_order is now strictly validated (JSON list of
  strings, 400 with a descriptive message otherwise) and popped from the
  payload before any further handling.
- display_controller: _apply_plugin_rotation_order defensively ignores a
  non-list value (keeps the existing rotation, logs a warning) and drops
  non-string entries; new logs carry the [DisplayController] prefix.
  Unit-tested both defensive paths.
- app.py: snapshot-read handler narrowed to OSError with debug logging;
  flask-compress ImportError now emits one structured warning with the
  install remedy.
- htmx-config: the response-error logger prints form FIELD NAMES only -
  values (API keys, passwords) never reach the console.
- plugin-order-list: saved order/exclusions normalized with Array.isArray
  (a saved "null" previously crashed .forEach); each row gained
  keyboard/touch-accessible move-up/move-down buttons (HTML5 drag events
  don't fire on most mobile browsers) that reorder and syncInputs()
  immediately alongside native drag.
- app-shell: window.installedPlugins setter always takes the new list
  (same-ID metadata/enabled updates were silently dropped); tab rebuild
  stays gated on ID changes. LED dot renderer reads the frame with ONE
  getImageData call instead of one per pixel (~9,200/frame at 192x48).
- plugins_manager: togglePlugin returns its request promise resolving the
  API outcome; the install flow now shows the "installed and enabled"
  toast (with Restart Now) only after enablement succeeds, and a warning
  without a restart offer when it fails.
- a11y: hamburger aria-label flips Open/Close with drawer state; both
  Advanced-section toggle buttons declare aria-controls/aria-expanded and
  the shared toggleSection() keeps aria-expanded in sync; move buttons
  have per-plugin aria-labels.
- Rotation/Vegas order-list bootstraps cap their retries (~5s) and show a
  reload hint instead of spinning forever; Alpine app-state lookups prefer
  [x-data="app()"] with a generic fallback.

Skipped, with reasons:
- executePluginAction arg order: caller (plugin_config.html) already
  passes (actionId, index, pluginId) matching the signature exactly.
- generateFieldHtml XSS, entity-unescape blocks, dotToNested pollution,
  and "app.loadInstalledPlugins" in app-shell: all inside the legacy
  client-side config cluster whose entry points are shadowed by
  plugins_manager.js / replaced by server-rendered forms (zero live
  callers, verified) - queued for wholesale deletion in the follow-up
  rather than patching dead code.
- custom-feeds-helpers.js findings (3): file was deleted in a prior commit.
- console.error/warn override removal and afterSwap script re-execution
  removal: deliberate pre-existing workarounds every partial's inline
  init currently depends on; reworking them safely needs isolated testing
  (follow-up), and the error suppression is already double-gated
  (insertBefore AND htmx match).
- "move durations bootstrap into a bundle": inline partial-scoped init is
  the established pattern for HTMX partials in this codebase.

Validation: all 40 web tests pass; py_compile on all touched Python; all
touched templates parse; rotation-order defensive paths unit-tested.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

web_interface/blueprints/api_v3.py

@@ -961,21 +961,22 @@ def save_main_config():
                     return jsonify({"status": "error", "message": "sync_follower_position must be left or right"}), 400
                 current_config["sync"]["follower_position"] = pos_val
 
-        # Handle primary rotation order (JSON array of plugin ids; same
-        # parse/validate pattern as vegas_plugin_order above)
+        # Handle primary rotation order: must be a JSON array of plugin-id
+        # strings. Reject anything else with a 400 rather than silently
+        # coercing, so a buggy client can't clear or corrupt the saved order.
         if 'plugin_rotation_order' in data:
+            raw_order = data.pop('plugin_rotation_order')
             try:
-                if isinstance(data['plugin_rotation_order'], str):
-                    parsed = json.loads(data['plugin_rotation_order'])
-                else:
-                    parsed = data['plugin_rotation_order']
-                if 'display' not in current_config:
-                    current_config['display'] = {}
-                current_config['display']['plugin_rotation_order'] = (
-                    list(parsed) if isinstance(parsed, (list, tuple)) else []
-                )
+                parsed = json.loads(raw_order) if isinstance(raw_order, str) else raw_order
             except (json.JSONDecodeError, TypeError, ValueError):
-                logger.warning("Malformed plugin_rotation_order ignored")
+                return jsonify({'status': 'error',
+                                'message': 'plugin_rotation_order must be valid JSON'}), 400
+            if not isinstance(parsed, list) or not all(isinstance(p, str) for p in parsed):
+                return jsonify({'status': 'error',
+                                'message': 'plugin_rotation_order must be a list of plugin-id strings'}), 400
+            if 'display' not in current_config:
+                current_config['display'] = {}
+            current_config['display']['plugin_rotation_order'] = parsed
 
         # Handle display durations
         duration_fields = [k for k in data.keys() if k.endswith('_duration') or k in ['default_duration', 'transition_duration']]