ActressRank collectors — Phase 0

Implemented:
  GET /health   D1 connectivity + core table counts (records a pipeline_runs row)

Planned (PRD §29-30, not implemented yet — do not call):
  POST /collect/works           Phase 1 — requires CommerceSourceAdapter (DMM)
  POST /collect/works/:source
  POST /update/work-details
  POST /resolve/actresses       Phase 2 — entity resolution
  POST /collect/rankings
  POST /calculate/scores        Phase 3 — ar-v0.1
  POST /detect/trends
  POST /generate/insights       Phase 6 — AI explanations
  POST /aggregate/site-metrics
  POST /import/affiliate-report Phase 5
  POST /reconcile/source-status