Keep gbrain current with this repo's code and refresh agent search
guidance in CLAUDE.md. Wraps the gstack-gbrain-sync orchestrator with
state probing, native code-surface registration, capability checks,
and a verdict block. Re-runnable, idempotent. Use when: "sync gbrain",
"refresh gbrain", "re-index this repo", "gbrain search isn't finding
things". (gstack)
