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

driver/wda_driver.py

@@ -4,6 +4,7 @@ from dataclasses import dataclass, field
 from typing import Any
 
 from core.errors import DeviceOfflineError, DriverError
+from core.models import ActiveApp
 from driver.base import Driver
 
 
@@ -161,6 +162,19 @@ class WDADriver(Driver):
         except Exception as exc:
             raise DriverError("ui tree retrieval failed") from exc
 
+    def active_app(self) -> ActiveApp | None:
+        client = self._require_client()
+        try:
+            response = client.execute_script("mobile: activeAppInfo")
+        except Exception as exc:
+            raise DriverError("active app retrieval failed") from exc
+        if not isinstance(response, dict):
+            return None
+        bundle_id = response.get("bundleId")
+        if not isinstance(bundle_id, str) or not bundle_id:
+            return None
+        return ActiveApp(platform="ios", bundle_id=bundle_id)
+
     def home(self) -> None:
         client = self._require_client()
         try: