feat: HA light output targets — cast LED colors to Home Assistant lights

New output target type `ha_light` that sends averaged LED colors to HA
light entities via WebSocket service calls (light.turn_on/turn_off):

Backend:
- HARuntime.call_service(): fire-and-forget WS service calls
- HALightOutputTarget: data model with light mappings, update rate, transition
- HALightTargetProcessor: processing loop with delta detection, rate limiting
- ProcessorManager.add_ha_light_target(): registration
- API schemas/routes updated for ha_light target type

Frontend:
- HA Light Targets section in Targets tab tree nav
- Modal editor: HA source picker, CSS source picker, light entity mappings
- Target cards with start/stop/clone/edit actions
- i18n keys for all new UI strings

server/src/wled_controller/api/schemas/system.py

@@ -64,6 +64,9 @@ class GpuInfo(BaseModel):
     memory_used_mb: float | None = Field(default=None, description="GPU memory used in MB")
     memory_total_mb: float | None = Field(default=None, description="GPU total memory in MB")
     temperature_c: float | None = Field(default=None, description="GPU temperature in Celsius")
+    app_memory_mb: float | None = Field(
+        default=None, description="GPU memory used by this app in MB"
+    )
 
 
 class PerformanceResponse(BaseModel):
@@ -74,6 +77,8 @@ class PerformanceResponse(BaseModel):
     ram_used_mb: float = Field(description="RAM used in MB")
     ram_total_mb: float = Field(description="RAM total in MB")
     ram_percent: float = Field(description="RAM usage percent")
+    app_cpu_percent: float = Field(description="App process CPU usage percent")
+    app_ram_mb: float = Field(description="App process resident memory in MB")
     gpu: GpuInfo | None = Field(default=None, description="GPU info (null if unavailable)")
     timestamp: datetime = Field(description="Measurement timestamp")