Fix CI workflow: cd to app/ directory for pip install and tests

.gitea/workflows/ci.yml

@@ -17,8 +17,11 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -e ".[dev]"
+          cd app && pip install -e ".[dev]"
       - name: Run tests
-        run: pytest tests/ -v --cov=src --cov-report=term-missing
+        run: |
+          cd app && pytest tests/ -v --cov=src --cov-report=term-missing
       - name: Check linting
-        run: pip install ruff && ruff check .
+        run: |
+          pip install ruff
+          cd app && ruff check .