Replace all emoji icons with Lucide SVGs, add accent color picker

- Replace all emoji characters across WebUI with inline Lucide SVG icons
  for cross-platform consistency (icon paths in icon-paths.js)
- Add accent color picker popover with 9 preset colors + custom picker,
  persisted to localStorage, updates all CSS custom properties
- Remove subtab separator line for cleaner look
- Color badge icons with accent color for visual pop
- Remove processing badge from target cards
- Fix hardcoded #4CAF50 in FPS labels and active badges to use CSS vars
- Replace CSS content emoji (▶) with pure CSS triangle

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

server/src/wled_controller/templates/modals/kc-editor.html

@@ -2,7 +2,7 @@
 <div id="kc-editor-modal" class="modal" role="dialog" aria-modal="true" aria-labelledby="kc-editor-title">
     <div class="modal-content">
         <div class="modal-header">
-            <h2 id="kc-editor-title" data-i18n="kc.add">🎨 Add Key Colors Target</h2>
+            <h2 id="kc-editor-title"><svg class="icon" viewBox="0 0 24 24"><path d="M12 22a1 1 0 0 1 0-20 10 9 0 0 1 10 9 5 5 0 0 1-5 5h-2.25a1.75 1.75 0 0 0-1.4 2.8l.3.4a1.75 1.75 0 0 1-1.4 2.8z"/><circle cx="13.5" cy="6.5" r=".5" fill="currentColor"/><circle cx="17.5" cy="10.5" r=".5" fill="currentColor"/><circle cx="6.5" cy="12.5" r=".5" fill="currentColor"/><circle cx="8.5" cy="7.5" r=".5" fill="currentColor"/></svg> <span data-i18n="kc.add">Add Key Colors Target</span></h2>
             <button class="modal-close-btn" onclick="closeKCEditorModal()" title="Close" data-i18n-aria-label="aria.close">&#x2715;</button>
         </div>
         <div class="modal-body">