Mark backend SQLite request-scoping task done and clean up test fixture

backend/tests/conftest.py

@@ -69,12 +69,12 @@ async def client(test_settings: Settings) -> AsyncClient:  # type: ignore[misc]
     """
     app = create_app(settings=test_settings)
 
-    # Bootstrap the database on app.state so Depends(get_db) works in tests.
-    # The ASGI lifespan is not triggered by ASGITransport, so we do this here.
+    # Bootstrap the database schema before making requests.  ASGITransport
+    # does not run the application lifespan, so we create the test SQLite file
+    # directly rather than relying on startup logic.
     db: aiosqlite.Connection = await aiosqlite.connect(test_settings.database_path)
     db.row_factory = aiosqlite.Row
     await init_db(db)
-    app.state.db = db
 
     transport: ASGITransport = ASGITransport(app=app)
     async with AsyncClient(transport=transport, base_url="http://test") as ac: