Add clone buttons, fix card navigation highlight, UI polish

- Add clone buttons to Audio Source and Value Source cards
- Fix command palette navigation destroying card highlight by skipping
  redundant data reload (skipLoad option on switchTab)
- Convert value source modal sliders to value-in-label pattern
- Change audio/value source modal footers to icon-only buttons
- Remove separator lines between card sections
- Add UI conventions to CLAUDE.md (card appearance, modal footer, sliders)

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

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

@@ -107,13 +107,13 @@ import {
 // Layer 5: audio sources
 import {
     showAudioSourceModal, closeAudioSourceModal, saveAudioSource,
-    editAudioSource, deleteAudioSource, onAudioSourceTypeChange,
+    editAudioSource, cloneAudioSource, deleteAudioSource, onAudioSourceTypeChange,
 } from './features/audio-sources.js';
 
 // Layer 5: value sources
 import {
     showValueSourceModal, closeValueSourceModal, saveValueSource,
-    editValueSource, deleteValueSource, onValueSourceTypeChange,
+    editValueSource, cloneValueSource, deleteValueSource, onValueSourceTypeChange,
     addSchedulePoint,
 } from './features/value-sources.js';
 
@@ -328,6 +328,7 @@ Object.assign(window, {
     closeAudioSourceModal,
     saveAudioSource,
     editAudioSource,
+    cloneAudioSource,
     deleteAudioSource,
     onAudioSourceTypeChange,
 
@@ -336,6 +337,7 @@ Object.assign(window, {
     closeValueSourceModal,
     saveValueSource,
     editValueSource,
+    cloneValueSource,
     deleteValueSource,
     onValueSourceTypeChange,
     addSchedulePoint,