Add OpenRGB device support for PC peripheral ambient lighting

New device type enabling control of keyboards, mice, RAM, GPU, and fans
via the OpenRGB SDK server (TCP port 6742). Includes auto-discovery,
health monitoring, state snapshot/restore, and fast synchronous pixel
send with brightness scaling. Also updates TODO.md with complexity notes.

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

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

@@ -134,6 +134,9 @@
   "device.mqtt_topic.placeholder": "mqtt://ledgrab/device/living-room",
   "device.ws_url": "Connection URL:",
   "device.ws_url.hint": "WebSocket URL for clients to connect and receive LED data",
+  "device.openrgb.url": "OpenRGB URL:",
+  "device.openrgb.url.hint": "OpenRGB server address (e.g. openrgb://localhost:6742/0)",
+  "device.type.openrgb": "OpenRGB",
   "device.url.hint": "IP address or hostname of the device (e.g. http://192.168.1.100)",
   "device.name": "Device Name:",
   "device.name.placeholder": "Living Room TV",