Added two new test cases to `src/tests/test_atomic_write.py`:
- `test_atomic_write_cleanup_on_failure`: Verifies that the temporary file is deleted if the write operation fails.
- `test_atomic_write_preserves_existing_on_failure`: Verifies that an existing destination file is preserved if the write operation fails.
These tests ensure the robustness of the `atomic_write` utility function.
Co-authored-by: PR0M3TH3AN <[email protected]>
