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_admin.py

@@ -16,6 +16,9 @@ class TestAdminEndpoints:
     async def test_list_users_admin(self, client: AsyncClient, admin_headers: dict):
         """Test listing users as admin."""
         response = await client.get("/api/v1/admin/users", headers=admin_headers)
+        print(f"\nDEBUG: status={response.status_code}, body={response.text}")
+        if response.status_code != 200:
+            print(f"DEBUG: response.json()={response.json()}")
         assert response.status_code == 200
         data = response.json()
         assert isinstance(data, list)