Add graph icon grid, search-to-graph nav, overlay on CSS cards, fix clipboard copy

- Convert graph editor add-entity menu to showTypePicker icon grid with SVG icons
- Add CSPT to graph add-entity picker and ALL_CACHES watcher
- Add graphNavigateToNode() — command palette navigates to graph node when graph tab active
- Add CSPT entities to global search palette results
- Add overlay toggle button on picture-based CSS cards (toggleCSSOverlay)
- Fix clipboard copy on non-HTTPS (LAN) with execCommand fallback for all copy functions
- Fix notification bell button vertical centering in test preview strip canvas
- Add overlay.toggle, search.group.cspt i18n keys (en/ru/zh)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/wled_controller/static/js/app.js

@@ -124,6 +124,7 @@ import {
     onAudioVizChange,
     applyGradientPreset,
     cloneColorStrip,
+    toggleCSSOverlay,
     copyEndpointUrl,
     onNotificationFilterModeChange,
     notificationAddAppColor, notificationRemoveAppColor,
@@ -423,6 +424,7 @@ Object.assign(window, {
     onAudioVizChange,
     applyGradientPreset,
     cloneColorStrip,
+    toggleCSSOverlay,
     copyEndpointUrl,
     onNotificationFilterModeChange,
     notificationAddAppColor, notificationRemoveAppColor,