Adds CloudApiSkillClient (Cloud API per-host sync endpoint + inventory
report), forwards since_version for incremental sync (full-replace on
first/stale), and forks a local override into a standalone local skill
when its cloud skill is revoked (design D9). Skill-side tests green (87
passed).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>