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/static/css/cards.css

@@ -312,6 +312,10 @@ body.cs-drag-active .card-drag-handle {
     font-size: 0.6rem;
 }
 
+.device-url-badge .icon {
+    color: var(--primary-text-color);
+}
+
 .card-subtitle {
     display: flex;
     align-items: center;
@@ -328,6 +332,10 @@ body.cs-drag-active .card-drag-handle {
     gap: 4px;
 }
 
+.card-meta .icon {
+    color: var(--primary-text-color);
+}
+
 .device-type-badge {
     font-size: 10px;
     font-weight: 700;
@@ -647,7 +655,7 @@ ul.section-tip li {
     font-weight: 400;
     opacity: 0.45;
     line-height: 1.1;
-    color: #4CAF50;
+    color: var(--primary-color);
 }
 
 .fps-unreachable {