gen-skill-docs.test.ts's 15 in-place generator spawns now render into
mkdtemp out-dirs (gitignored-artifact reads repointed; the handshake
scan's silent console.warn degrade became a hard assertion); its
tracked-tree reads (freshness dry-run, SKILL.md content pins) stay
reads. catalog-trim needed no change beyond the earlier main() guard —
its import is now side-effect-free (pinned by the import-purity test).
Both TREE_MUTATING entries deleted in this commit, per the transition
rule: an entry leaves in the same commit as the file's last in-place
write.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
