[ygyang11]

Summary

• add persistent /goal state, independent transcript evaluator, continuation driver, pause/resume/clear lifecycle, and session restoration
• integrate goal execution with REPL background completion, cancellation, plan-mode exclusion, replay/export rendering, status UI, and usage accounting
• support headless /goal runs with aggregated output, deterministic --max-turns, and background-result continuation while preserving normal single-shot behavior

Testing

• ruff check src tests
• mypy src
• pytest (2695 passed, 3 skipped)
• real headless and interactive smoke scenarios covering background completion, evaluator continuation, Ctrl+C/resume, blocked outcomes, and recommendation questions followed by autonomous continuation