feat: add plugin runtime and cross-device task orchestration

artemis/controllers/device_controller.py

@@ -50,6 +50,7 @@ class ScreenDataResponse(BaseModel):
     width: int = Field(default=1080, description="Device screen width in pixels")
     height: int = Field(default=2400, description="Device screen height in pixels")
     platform: str = Field(default="android", description="Platform identifier")
+    observation_text: str = ""
 
 
 class MobileDeviceController(ABC):

artemis/controllers/unified_controller.py

@@ -267,6 +267,7 @@ class UnifiedMobileController:
             width=data.width,
             height=data.height,
             platform=data.platform,
+            observation_text=data.observation_text,
         )
 
     async def find_element(