Use pytest -k filter for API integration tests

Replace explicit file listing with `pytest tests/ -k "_int"` to automatically discover all integration tests in any subdirectory. This improves maintainability by eliminating the need to manually update the workflow when adding new integration test files.

Excludes:
- tests/driver/ (runs separately in database-integration-tests)
- tests/test_graphiti_mock.py (runs separately in database-integration-tests)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/unit_tests.yml

@@ -155,4 +155,6 @@ jobs:
           ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
           GOOGLE_API_KEY: ${{ secrets.GOOGLE_API_KEY }}
         run: |
-          uv run pytest tests/test_*_int.py tests/llm_client/test_anthropic_client_int.py tests/utils/maintenance/test_temporal_operations_int.py tests/cross_encoder/test_bge_reranker_client_int.py
+          uv run pytest tests/ -k "_int" \
+            --ignore=tests/driver/ \
+            --ignore=tests/test_graphiti_mock.py