refactor(device): remove single-device state and test branches

apps/admin_console/routers/system.py

@@ -111,7 +111,7 @@ async def select_active_device(request: SelectDeviceRequest):
     if not serial:
         raise HTTPException(status_code=400, detail="Device serial cannot be empty.")
 
-    readiness_engine.set_active_device_serial(serial)
+    readiness_engine.set_probe_target_serial(serial)
     # Return updated readiness
     report = await readiness_engine.run_all(force_refresh=True)
     return {
@@ -192,7 +192,7 @@ async def connect_adb_server(payload: ConnectAdbServerRequest, request: Request)
 
     response: dict[str, object] = {"connection_result": connection_result}
     if connection_result["success"]:
-        readiness_engine.set_active_device_serial(None)
+        readiness_engine.set_probe_target_serial(None)
         readiness_engine.invalidate_cache()
         response["report"] = await readiness_engine.run_all(force_refresh=True)
     return response
@@ -214,7 +214,7 @@ async def use_local_adb_server(request: Request, persist: bool = True):
     """Restore the standard local ADB server without touching a remote daemon."""
     _require_local_admin_request(request)
     connection_result = await adb_server_connection.use_local_server(persist=persist)
-    readiness_engine.set_active_device_serial(None)
+    readiness_engine.set_probe_target_serial(None)
     readiness_engine.invalidate_cache()
     updated_report = await readiness_engine.run_all(force_refresh=True)
     return {

apps/admin_console/routers/tasks.py

@@ -140,7 +140,10 @@ async def run_task(request: RunRequest):
     # polling intervals cannot start through a stale Ready state. Use the
     # bounded submission probe: the full diagnostics path also scans packages,
     # emulator installations, Android version, and screen size.
-    target_serial = request.device_serial or readiness_engine.get_active_device_serial()
+    # With no explicit serial the probe itself resolves a live target (it
+    # prefers the diagnostics target preference, then any unlocked ready
+    # device); the verified serial is bound below.
+    target_serial = request.device_serial
     device_probe = await readiness_engine.run_device_submission_probe(
         target_serial=target_serial
     )
@@ -164,10 +167,6 @@ async def run_task(request: RunRequest):
         # invalid, enqueue_tasks rejects the submission with a clear error.
         if verified_serial and not request.device_serial:
             target_serial = verified_serial
-        # The probe verified a live device either way: keep the global active
-        # serial in sync even when the caller pinned the target explicitly.
-        if verified_serial and readiness_engine.get_active_device_serial() != verified_serial:
-            readiness_engine.set_active_device_serial(verified_serial)
 
     return await task_queue_service.enqueue_tasks(
         incoming_goals,