/refine [focus] fires the existing background review fork
(AIAgent._spawn_background_review) immediately instead of waiting for
the automatic 10-turn memory / 10-iteration skill nudge counters.
Optional focus instructions are appended to the review prompt so the
fork prioritizes what the user asked for (e.g. '/refine save the
deploy workflow as a skill').
- New optional focus parameter threaded through
_spawn_background_review -> spawn_background_review_thread.
Automatic post-turn reviews pass None and their prompts are
byte-identical to before.
- CLI handler snapshots conversation_history; gateway handler pulls
the idle session's cached AIAgent from _agent_cache (rejected while
the agent is running).
- Review runs in a daemon thread against the snapshot — live
conversation, message alternation, and prompt cache untouched.
- Slack stays under the 50-slash cap via /hermes refine.
Adapted from the /refine concept in Prime Intellect's Prime-Agent
(Continual Harness); Hermes' equivalent durable state is the
memory + skill stores, so the review fork is the natural target.
