Add command palette entity selector for all editor dropdowns

Replace plain <select> dropdowns with a searchable command palette modal
for 16 entity selectors across 6 editors (targets, streams, CSS sources,
value sources, audio sources, pattern templates). Unified EntityPalette
singleton + EntitySelect wrapper in core/entity-palette.js.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/sw.js

@@ -7,7 +7,7 @@
  *   - Navigation: network-first with offline fallback
  */
 
-const CACHE_NAME = 'ledgrab-v16';
+const CACHE_NAME = 'ledgrab-v17';
 
 // Only pre-cache static assets (no auth required).
 // Do NOT pre-cache '/' — it requires API key auth and would cache an error page.