[codex] Add memory evaluation and forgetter workflows

[lsy040203]

Summary

• add memory evaluation foundations, rubrics, judge orchestration, replay/report artifacts, and regression fixtures
• add event-driven memory lifecycle components and hardened forgetter safety semantics
• document evaluation and forgetter workflows with focused pytest coverage

Validation

• C:\Users\HP\miniconda3\envs\minicode\python.exe -m pytest tests/test_abc_adapters.py tests/test_rubrics.py tests/test_evaluation.py tests/test_forgetting_eval.py tests/test_memory_judge.py tests/test_evaluation_artifacts.py tests/test_evaluation_cases.py tests/test_memoryos_event_driven.py tests/test_forgetter.py -q -> 83 passed

Note

Full pytest tests -q currently hits an upstream extractor collection error in extractors/preference_extractor.py under Python 3.11 before reaching unrelated tests.