Fix backend test suite - all 20 tests passing

- Updated JWT tokens to include privlevel for authorization
- Fixed test fixtures to properly hash passwords with bcrypt
- Fixed client fixture to share database session with test fixtures
- Reordered deck router routes to prevent conflicts
- Removed relationship fields from FolderResponse schema
- Updated conftest.py with proper async session management

backend/tests/test_decks.py

@@ -141,6 +141,7 @@ class TestDeckManagement:
         
         # List folders
         response = await client.get("/api/v1/decks/folders", headers=auth_headers)
+        print(f"\nDEBUG list_folders: status={response.status_code}, body={response.text}")
         assert response.status_code == 200
         data = response.json()
         assert isinstance(data, list)