fix: hardcode database connection details in CI workflow for consistency

.gitea/workflows/ci.yml

@@ -61,11 +61,11 @@ jobs:
       - name: Run tests
         env:
           DATABASE_DRIVER: postgresql+psycopg2
-          DATABASE_HOST: ${ { env.DB_HOST } }
+          DATABASE_HOST: postgres
           DATABASE_PORT: 5432
-          DATABASE_USER: ${ { env.DB_USER } }
-          DATABASE_PASSWORD: ${ { env.DB_PASSWORD } }
-          DATABASE_NAME: ${ { env.DB_NAME } }
+          DATABASE_USER: calminer
+          DATABASE_PASSWORD: calminer_password
+          DATABASE_NAME: calminer_test
         run: |
           pytest tests/ --cov=.