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/htmx-config.js

@@ -12,44 +12,39 @@
                             if (!target) {
                                 console.warn('[HTMX] Target is null, skipping swap');
                                 event.detail.shouldSwap = false;
-                                return false;
+                                return;
                             }
                             
                             // Check if target is a valid DOM element
                             if (!(target instanceof Element)) {
                                 console.warn('[HTMX] Target is not a valid Element, skipping swap');
                                 event.detail.shouldSwap = false;
-                                return false;
+                                return;
                             }
                             
                             // Check if target has a parent node (required for insertBefore)
                             if (!target.parentNode) {
                                 console.warn('[HTMX] Target has no parent node, skipping swap');
                                 event.detail.shouldSwap = false;
-                                return false;
+                                return;
                             }
                             
                             // Ensure target is in the DOM
                             if (!document.body.contains(target) && !document.head.contains(target)) {
                                 console.warn('[HTMX] Target is not in DOM, skipping swap');
                                 event.detail.shouldSwap = false;
-                                return false;
+                                return;
                             }
                             
                             // Additional check: ensure parent is also in DOM
                             if (target.parentNode && !document.body.contains(target.parentNode) && !document.head.contains(target.parentNode)) {
                                 console.warn('[HTMX] Target parent is not in DOM, skipping swap');
                                 event.detail.shouldSwap = false;
-                                return false;
                             }
-                            
-                            // All checks passed, allow swap
-                            return true;
                         } catch (e) {
                             // If validation fails, cancel swap
                             console.warn('[HTMX] Error validating target:', e);
                             event.detail.shouldSwap = false;
-                            return false;
                         }
                     });