fix(web): widget cache-busting, dead frontend code, and dependency pins (#656)

- Plugin-supplied widgets load as /static/plugin-widgets/...js?v=<plugin
  version>, so an update isn't hidden behind the year-long immutable cache.
- Fire-and-forget loadInstalledPlugins() calls catch the rejection it has
  already reported, so the global handler no longer adds a second toast.
- Timezone picker renders again when the General partial is re-injected.
- Remove dead code: executePluginAction's six plugin-id fallbacks and
  [DEBUG] logging, window.currentPluginConfig and every read of it, the
  file-upload JSON delete branch, unused PluginAPI / PluginInstallManager /
  PluginStateManager helpers, loadPluginWidgetsFromManifest, the stale
  install_manager.js and LEDVisibility fallbacks, error_handler.js's global
  escapeHtml, 13 unused CSS rules, and stale comments/no-op returns.
- pytz < 2027, psutil < 7 in requirements-test.txt, pytest-cov < 8.
- Pin anthropics/claude-code-action to the commit v1 resolves to.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

web_interface/static/v3/js/app-shell.js

@@ -651,12 +651,7 @@ function markPanelLoadFailed(event) {
                             // Also update window.installedPlugins for consistency
                             window.installedPlugins = this.installedPlugins;
                             debugLog(`[FULL] Loaded ${this.installedPlugins.length} plugins:`, this.installedPlugins.map(p => p.id));
-                            
-                            // Debug: Log enabled status for each plugin
-                            this.installedPlugins.forEach(plugin => {
-                                debugLog(`[DEBUG Alpine] Plugin ${plugin.id}: enabled=${plugin.enabled} (type: ${typeof plugin.enabled})`);
-                            });
-                            
+
                             this.updatePluginTabs();
                         } else {
                             console.error('[FULL] Failed to load plugins:', data.message);