Fix Adalight power toggle using cached idle client and tracked state

Serial devices now route power on/off through the cached idle client
instead of opening a new serial connection (which caused PermissionError).
Adds tracked power_on state to DeviceState since Adalight has no
hardware power query.

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

server/src/wled_controller/api/routes/devices.py

@@ -401,6 +401,7 @@ async def get_device_power(
     device_id: str,
     _auth: AuthRequired,
     store: DeviceStore = Depends(get_device_store),
+    manager: ProcessorManager = Depends(get_processor_manager),
 ):
     """Get current power state from the device."""
     device = store.get_device(device_id)
@@ -410,6 +411,11 @@ async def get_device_power(
         raise HTTPException(status_code=400, detail=f"Power control is not supported for {device.device_type} devices")
 
     try:
+        # Serial devices: use tracked state (no hardware query available)
+        ds = manager._devices.get(device_id)
+        if device.device_type in ("adalight", "ambiled") and ds:
+            return {"on": ds.power_on}
+
         provider = get_provider(device.device_type)
         on = await provider.get_power(device.url)
         return {"on": on}
@@ -424,6 +430,7 @@ async def set_device_power(
     body: dict,
     _auth: AuthRequired,
     store: DeviceStore = Depends(get_device_store),
+    manager: ProcessorManager = Depends(get_processor_manager),
 ):
     """Turn device on or off."""
     device = store.get_device(device_id)
@@ -437,11 +444,22 @@ async def set_device_power(
         raise HTTPException(status_code=400, detail="'on' must be a boolean")
 
     try:
-        provider = get_provider(device.device_type)
-        await provider.set_power(
-            device.url, on,
-            led_count=device.led_count, baud_rate=device.baud_rate,
-        )
+        # For serial devices, use the cached idle client to avoid port conflicts
+        ds = manager._devices.get(device_id)
+        if device.device_type in ("adalight", "ambiled") and ds:
+            if on:
+                # Restore idle state (static color or stay dark)
+                if ds.static_color is not None:
+                    await manager.send_static_color(device_id, ds.static_color)
+            else:
+                await manager._send_clear_pixels(device_id)
+            ds.power_on = on
+        else:
+            provider = get_provider(device.device_type)
+            await provider.set_power(
+                device.url, on,
+                led_count=device.led_count, baud_rate=device.baud_rate,
+            )
         return {"on": on}
     except Exception as e:
         logger.error(f"Failed to set power for {device_id}: {e}")

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

@@ -55,6 +55,8 @@ class DeviceState:
     # Calibration test mode (works independently of target processing)
     test_mode_active: bool = False
     test_mode_edges: Dict[str, Tuple[int, int, int]] = field(default_factory=dict)
+    # Tracked power state for serial devices (no hardware query)
+    power_on: bool = True
 
 
 class ProcessorManager: