Add CPU/GPU names on perf charts, reusable color picker, and header toolbar redesign

- Show CPU and GPU model names as overlays on performance chart cards
- Add cpu_name field to performance API with cross-platform detection
- Extract reusable color-picker popover module (9 presets + custom picker)
- Per-chart color customization for CPU/RAM/GPU performance charts
- Redesign header: compact toolbar container with icon-only buttons
- Compact language dropdown (EN/RU/ZH), icon-only login/logout
- Use accent color for FPS charts, range slider accent, dashboard icons

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

server/src/wled_controller/static/css/components.css

@@ -195,6 +195,7 @@ select:disabled {
 input[type="range"] {
     width: 100%;
     margin: 8px 0;
+    accent-color: var(--primary-color);
 }
 
 /* Better password field appearance */
@@ -394,8 +395,7 @@ input:-webkit-autofill:focus {
 .modal-header-btn:focus-visible,
 .tab-btn:focus-visible,
 .stream-tab-btn:focus-visible,
-.search-toggle:focus-visible,
-.theme-toggle:focus-visible,
+.header-btn:focus-visible,
 .tutorial-trigger-btn:focus-visible,
 .tutorial-close-btn:focus-visible,
 .btn-expand-collapse:focus-visible,