Verification: structural review — clean ✅

Reviewed the full diff (2 files, +202/-6). Checked:

1. Persist ordering — _persist_session moved AFTER transform_llm_output AND post_llm_call hooks, so hook-modified responses are persisted to both session log and SQLite DB. Previously, hooks could override final_response but the pre-hook version was persisted.
2. _sync_final_response_to_last_assistant — called twice (before post_llm_call + after), ensuring the in-memory assistant message matches the current final_response at each stage. Walks backward to find the last assistant message — safe for multi-turn.
3. post_llm_call response override — iterates _post_results from invoke_hook, extracts overrides via _extract_post_llm_response_override (handles str, dict with response/override_response/assistant_response keys). Breaks on first override — intentional (first plugin wins).
4. _response_transformed flag — set in post_llm_call override path, consumed in return value (line 336 in current code). Dead variable concern eliminated.
5. No double-persist — _persist_session is called exactly once, after all hooks complete. The pre-hook call was removed.

No issues found. Test coverage verifies both transform_llm_output and post_llm_call override paths persist correctly.