feat: add backup.retain_days config and local docker-compose for integration tests

- Add [backup] retain_days to config (default 1); --days becomes optional
- Add scripts/docker-compose.yml (azurite) for local integration testing
- Integration tests now use assets/local.toml and localhost endpoints
- Update .gitignore and CLAUDE.md accordingly

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_integration.py

@@ -14,7 +14,7 @@ from order_bak.csv_utils import read_csv
 from order_bak.delete import delete_orders
 from order_bak.scan import scan_orders
 
-CONFIG_PATH = Path(__file__).parent.parent / "assets" / "s101.toml"
+CONFIG_PATH = Path(__file__).parent.parent / "assets" / "local.toml"
 
 CONNECTION_STRING = os.environ.get(
     "ORDER_BAK_TEST_CONNECTION_STRING",
@@ -23,9 +23,9 @@ CONNECTION_STRING = os.environ.get(
         "AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/"
         "K1SZFPTOtr/KBHBeksoGMGw==;"
         "DefaultEndpointsProtocol=http;"
-        "BlobEndpoint=http://192.168.9.101:10000/devstoreaccount1;"
-        "QueueEndpoint=http://192.168.9.101:10001/devstoreaccount1;"
-        "TableEndpoint=http://192.168.9.101:10002/devstoreaccount1;"
+        "BlobEndpoint=http://localhost:10000/devstoreaccount1;"
+        "QueueEndpoint=http://localhost:10001/devstoreaccount1;"
+        "TableEndpoint=http://localhost:10002/devstoreaccount1;"
     ),
 )