feat(perception): expose active app metadata in UI tree

tools/_device.py

@@ -1,8 +1,13 @@
 from __future__ import annotations
 
+import logging
+
+from core.models import ActiveApp
 from device.manager import DEFAULT_MANAGER, DeviceManager
 from driver.base import Driver
 
+logger = logging.getLogger(__name__)
+
 
 def get_driver(
     device_id: str | None = None,
@@ -10,3 +15,15 @@ def get_driver(
     manager: DeviceManager | None = None,
 ) -> Driver:
     return (manager or DEFAULT_MANAGER).active_driver(device_id)
+
+
+def get_active_app_info(driver: Driver) -> ActiveApp | None:
+    """Best-effort foreground application lookup that cannot block observation."""
+    try:
+        return driver.active_app()
+    except Exception:
+        logger.warning(
+            "active app retrieval failed; continuing without app metadata",
+            exc_info=True,
+        )
+        return None