refactor: reorganize backend module boundaries

tests/test_transfer_job_manager.py

@@ -3,11 +3,11 @@ from pathlib import Path
 from types import SimpleNamespace
 from unittest.mock import patch, MagicMock
 
-from app.platform.config import settings
+from app.runtime.config import settings
 from app.domain.context import MediaInfo
 from app.domain.meta.metavideo import MetaVideo
 from app.chain.transfer import JobManager, TransferChain
-from app.services.history import (
+from app.application.history import (
     clear_transfer_failures,
     failed_retry_count,
     record_transfer_failure,