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/locales/en.json

@@ -533,6 +533,7 @@
   "dashboard.perf.ram": "RAM",
   "dashboard.perf.gpu": "GPU",
   "dashboard.perf.unavailable": "unavailable",
+  "dashboard.perf.color": "Chart color",
   "dashboard.poll_interval": "Refresh interval",
   "profiles.title": "Profiles",
   "profiles.empty": "No profiles configured. Create one to automate target activation.",

server/src/wled_controller/static/locales/ru.json

@@ -533,6 +533,7 @@
   "dashboard.perf.ram": "ОЗУ",
   "dashboard.perf.gpu": "ГП",
   "dashboard.perf.unavailable": "недоступно",
+  "dashboard.perf.color": "Цвет графика",
   "dashboard.poll_interval": "Интервал обновления",
   "profiles.title": "Профили",
   "profiles.empty": "Профили не настроены. Создайте профиль для автоматизации целей.",

server/src/wled_controller/static/locales/zh.json

@@ -533,6 +533,7 @@
   "dashboard.perf.ram": "内存",
   "dashboard.perf.gpu": "GPU",
   "dashboard.perf.unavailable": "不可用",
+  "dashboard.perf.color": "图表颜色",
   "dashboard.poll_interval": "刷新间隔",
   "profiles.title": "配置文件",
   "profiles.empty": "尚未配置配置文件。创建一个以自动化目标激活。",