Add tests for #515: filelock version independence

[Serhan-Asad]

Summary

Adds tests to address the CI failure caused by filelock v3.21.0 behavior changes (#515).

Test Files

• tests/test_auto_deps_lock.py

Test Coverage

• Total Tests: 5
• Framework: pytest
• Status: All passing

What These Tests Verify

1. Concurrent calls serialize and share cache (existing, fixed)
2. Lock file location (existing, fixed)
3. No CWD artifacts (existing)
4. Filelock version independence (new) - verifies auto_deps works regardless of whether filelock deletes lock files on release
5. Force-scan ignores cache (new) - verifies force_scan=True bypasses cached results

Test Execution

pytest tests/test_auto_deps_lock.py -v

Next Steps

1. Review the generated tests
2. Run tests locally to verify
3. Adjust tests if needed
4. Mark PR as ready for review

Closes #515

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