- Add POST/GET /skill-registry/skills/:sourceId/:slug/ratings routes
- Import skillRatingService in skill-registry routes
- Add upsertCommunityRatingsStub() in fetcher, called after each skill upsert
- Import communityRatings from schema in fetcher
- Update list() and getById() in skill-registry.ts to LEFT JOIN communityRatings
- Include averageRating, ratingCount, taskCount, avgCostUsd, lastUsedAt in SkillListItem
- Add agentSkills usage aggregation via LEFT JOIN + SUM/AVG/MAX
- Add fire-and-forget recordUsageForAgent call in heartbeat after finalizeAgentStatus
- Dynamic import keeps skill-registry-ratings off critical startup path
- All 44 skill-registry tests pass, full server suite (536) green
- SkillSourceConfig type + BUILT_IN_SOURCES (3 sources: anthropic, schwepps, daymade)
- fetchAllSources() fetches from anthropic-marketplace and github-tree source types
- parseSkillFrontmatter() extracts name/description from SKILL.md YAML blocks
- Idempotency: checks version exists before fetching, skips re-download on same SHA
- Caches SKILL.md to skills/cache/<skill-id>/<sha>/SKILL.md on disk
- Inserts skills, skill_versions, and skill_files rows into registry.db
- All 7 tests passing (TDD GREEN)
