fix: preserve custom algorithm order across reload

[DevChiniwala]

Summary

Preserve explicit algorithm ordering across SmashConfig save/load and reload-time resmashing.

Root cause

SmashConfig._algorithm_order was an in-memory-only preference. It was not serialized, and resmash() passed the original full order even after disabling algorithms that should not be reapplied. Duplicate names were also accepted by the set-based validation.

Fix

• Serialize and restore algorithm_order.
• Clear stale custom ordering when loading legacy configs.
• Filter custom ordering to algorithms reapplied during resmash().
• Reject duplicate algorithm names.
• Document the persistence behavior.

Validation

• Added focused tests for save/load persistence, resmash filtering, and duplicate rejection.
• pytest --basetemp check-tmp-pr-final tests/config/test_smash_config_serialization.py tests/engine/test_save.py::test_save_pruna_model_path_types -q — 5 passed.
• Legacy config without algorithm_order was loaded successfully and cleared stale ordering.
• ruff check src/pruna/config/smash_config.py src/pruna/engine/load.py tests/config/test_smash_config_serialization.py — passed.
• ty check src/pruna/config/smash_config.py src/pruna/engine/load.py — passed.

GPU validation was not required; this change protects configuration and reload state.

AI assistance disclosure

This contribution was developed with AI assistance. The implementation, tests, and validation were reviewed against the repository code and executed locally.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.