fix: resolve CI issues - clean up unused imports and fix linting errors

.gitea/workflows/ci.yml

@@ -14,8 +14,10 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: '3.11'
-      - name: Install and test
+      - name: Run tests and linting
         run: |
-          cd app
+          python -m pip install --upgrade pip
           pip install -e ".[dev]"
-          pytest tests/ -v
+          python -m pytest tests/ -v --cov=src --cov-report=term-missing
+          pip install ruff
+          ruff check src/