Fix localization: Update dynamic content when language changes

Fixed issues where device details and display badges were not updating
when switching languages:

Changes:
- Updated updateAllText() to reload displays and devices when language changes
- Added translations to createDeviceCard() for all dynamic text:
  * Device status badges (Processing/Idle)
  * Device info labels (URL, LED Count, Display)
  * Metrics labels (Actual FPS, Target FPS, Frames, Errors)
  * Button labels (Start, Stop, Settings, Calibrate, Remove)
- Updated loadDevices() error messages to use translations
- Added missing translations to locale files:
  * device.metrics.actual_fps, target_fps, frames, errors

Now when switching between English and Russian, all device cards and
display information updates correctly, including:
- Primary/Secondary display badges
- Device status badges
- All labels and button text
- Metrics labels when processing

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

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

@@ -64,6 +64,10 @@
   "device.removed": "Device removed successfully",
   "device.started": "Processing started",
   "device.stopped": "Processing stopped",
+  "device.metrics.actual_fps": "Actual FPS",
+  "device.metrics.target_fps": "Target FPS",
+  "device.metrics.frames": "Frames",
+  "device.metrics.errors": "Errors",
   "settings.title": "Device Settings",
   "settings.brightness": "Brightness:",
   "settings.brightness.hint": "Global brightness for this WLED device (0-100%)",