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/settings.js

@@ -7,6 +7,7 @@ import { API_BASE, fetchWithAuth } from '../core/api.js';
 import { Modal } from '../core/modal.js';
 import { showToast, showConfirm } from '../core/ui.js';
 import { t } from '../core/i18n.js';
+import { ICON_UNDO, ICON_DOWNLOAD } from '../core/icons.js';
 
 // Simple modal (no form / no dirty check needed)
 const settingsModal = new Modal('settings-modal');
@@ -207,8 +208,8 @@ export async function loadBackupList() {
                     <span>${date}</span>
                     <span style="color:var(--text-muted);margin-left:0.3rem;">${sizeKB} KB</span>
                 </div>
-                <button class="btn btn-icon btn-secondary" onclick="restoreSavedBackup('${b.filename}')" title="${t('settings.saved_backups.restore')}" style="padding:2px 6px;font-size:0.8rem;">&#x21BA;</button>
-                <button class="btn btn-icon btn-secondary" onclick="downloadSavedBackup('${b.filename}')" title="${t('settings.saved_backups.download')}" style="padding:2px 6px;font-size:0.8rem;">&#x2B07;</button>
+                <button class="btn btn-icon btn-secondary" onclick="restoreSavedBackup('${b.filename}')" title="${t('settings.saved_backups.restore')}" style="padding:2px 6px;font-size:0.8rem;">${ICON_UNDO}</button>
+                <button class="btn btn-icon btn-secondary" onclick="downloadSavedBackup('${b.filename}')" title="${t('settings.saved_backups.download')}" style="padding:2px 6px;font-size:0.8rem;">${ICON_DOWNLOAD}</button>
                 <button class="btn btn-icon btn-secondary" onclick="deleteSavedBackup('${b.filename}')" title="${t('settings.saved_backups.delete')}" style="padding:2px 6px;font-size:0.8rem;">&#x2715;</button>
             </div>`;
         }).join('');