Add mock LED device type for testing without hardware

Virtual device with configurable LED count, RGB/RGBW mode, and simulated
send latency. Includes full provider/client implementation, API schema
support, and frontend add/settings modal integration.

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

server/src/wled_controller/core/processing/processor_manager.py

@@ -129,6 +129,15 @@ class ProcessorManager:
         ds = self._devices.get(device_id)
         if ds is None:
             return None
+        # Read mock-specific fields from persistent storage
+        send_latency_ms = 0
+        rgbw = False
+        if self._device_store:
+            dev = self._device_store.get_device(ds.device_id)
+            if dev:
+                send_latency_ms = getattr(dev, "send_latency_ms", 0)
+                rgbw = getattr(dev, "rgbw", False)
+
         return DeviceInfo(
             device_id=ds.device_id,
             device_url=ds.device_url,
@@ -137,6 +146,8 @@ class ProcessorManager:
             baud_rate=ds.baud_rate,
             software_brightness=ds.software_brightness,
             test_mode_active=ds.test_mode_active,
+            send_latency_ms=send_latency_ms,
+            rgbw=rgbw,
         )
 
     # ===== EVENT SYSTEM (state change notifications) =====

server/src/wled_controller/core/processing/target_processor.py

@@ -69,6 +69,8 @@ class DeviceInfo:
     baud_rate: Optional[int] = None
     software_brightness: int = 255
     test_mode_active: bool = False
+    send_latency_ms: int = 0
+    rgbw: bool = False
 
 
 @dataclass

server/src/wled_controller/core/processing/wled_target_processor.py

@@ -86,6 +86,8 @@ class WledTargetProcessor(TargetProcessor):
                 device_info.device_type, device_info.device_url,
                 use_ddp=True, led_count=device_info.led_count,
                 baud_rate=device_info.baud_rate,
+                send_latency_ms=device_info.send_latency_ms,
+                rgbw=device_info.rgbw,
             )
             await self._led_client.connect()
             logger.info(