0537e2600d
Self-review follow-ups on the salvage of #33177 + #33188 + #33209: W3 (real, lock_path.write_text was non-atomic AND the read path silently resets data to an empty installed dict on JSONDecodeError — a crash mid- write could nuke ALL hub provenance, not just official-optional). Switch to the same mkstemp + fsync + atomic_replace pattern that _write_manifest already uses in this module. W5 (dead code) — _validate_category_name had one caller on origin/main (install_from_quarantine), swapped to _validate_install_parent_path by #33177. Remove the now-unused definition to avoid the attractive-nuisance of contributors picking the wrong validator. Behavior preserved on the happy path; verified all 200 skills/hub tests plus the three E2E scenarios (destructive restore, backfill idempotency, adversarial nonexistent skill) still pass after both fixes.