fix(root): dispose api test engine after pytest session

Dispose the async SQLAlchemy engine at test-session teardown so
apps/api:test exits cleanly after pytest finishes.

Co-Authored-By: First Fluke <our.first.fluke@gmail.com>

Author: gracefullight

apps/api/tests/conftest.py

@@ -45,5 +45,6 @@ def client() -> Iterator[TestClient]:
 def cleanup_test_database() -> Iterator[None]:
     """Remove the process-local SQLite file after the test session."""
     yield
+    asyncio.run(engine.dispose())
     if TEST_DB_PATH.exists():
         TEST_DB_PATH.unlink()