feat(admin): rewire launch-app to check-for-updates UI nav + frontend polling

admin_server.py

@@ -2841,11 +2841,14 @@ async def admin_msfs_sync_task(task_id: str):
 
 @app.post("/api/admin/msfs-sync/launch-app")
 async def admin_msfs_sync_launch():
-    """Launch the MS Field Service app on the connected phone."""
+    """Launch MS Field Service app, navigate to Check for Updates via UI nav.
+
+    Taps globe icon in top-right, waits 15s, taps Check for Updates button,
+    then waits for the phone's offline DB to stabilize.
+    """
     try:
-        async with httpx.AsyncClient(timeout=15) as client:
-            resp = await client.post(f"{EXTRACTION_SYNC_BASE}/api/sync/start")
-            # The start endpoint already launches the app
+        async with httpx.AsyncClient(timeout=30) as client:
+            resp = await client.post(f"{EXTRACTION_SYNC_BASE}/api/sync/check-for-updates")
             return resp.json()
     except httpx.RequestError as e:
         raise HTTPException(502, f"Extraction server unreachable: {e}")