feat: Add bucketUrl to DeployedConfig

Add bucketUrl field to schema and query so mobile can get
the bucket URL dynamically from the backend instead of
hardcoding it.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/operations/config.gql

@@ -15,5 +15,6 @@ query getDeployedConfig {
       priority
     }
     defaultAndroidRecordingFormat
+    bucketUrl
   }
 }