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/js/features/calibration.js

@@ -10,6 +10,7 @@ import { showToast } from '../core/ui.js';
 import { Modal } from '../core/modal.js';
 import { closeTutorial, startCalibrationTutorial } from './tutorials.js';
 import { startCSSOverlay, stopCSSOverlay } from './color-strips.js';
+import { ICON_WARNING, ICON_ROTATE_CW, ICON_ROTATE_CCW } from '../core/icons.js';
 
 /* ── CalibrationModal subclass ────────────────────────────────── */
 
@@ -371,7 +372,7 @@ export function updateCalibrationPreview() {
     const mismatch = inCSS
         ? (declaredCount > 0 && total > declaredCount)
         : (total !== declaredCount);
-    document.getElementById('cal-total-leds-inline').textContent = (mismatch ? '\u26A0 ' : '') + total;
+    document.getElementById('cal-total-leds-inline').innerHTML = (mismatch ? ICON_WARNING + ' ' : '') + total;
     if (totalEl) totalEl.classList.toggle('mismatch', mismatch);
 
     const startPos = document.getElementById('cal-start-position').value;
@@ -386,7 +387,7 @@ export function updateCalibrationPreview() {
     const direction = document.getElementById('cal-layout').value;
     const dirIcon = document.getElementById('direction-icon');
     const dirLabel = document.getElementById('direction-label');
-    if (dirIcon) dirIcon.textContent = direction === 'clockwise' ? '↻' : '↺';
+    if (dirIcon) dirIcon.innerHTML = direction === 'clockwise' ? ICON_ROTATE_CW : ICON_ROTATE_CCW;
     if (dirLabel) dirLabel.textContent = direction === 'clockwise' ? 'CW' : 'CCW';
 
     const deviceId = document.getElementById('calibration-device-id').value;