Nexus Digest Worker
  GET /subscribe           — subscribe form
  POST /api/subscribe     — send confirmation email
  GET /api/confirm?token  — confirmation page
  POST /api/confirm       — finalize subscription
  GET /run/<name>          — fetch, rank, send
  GET /run/<name>?dry=1    — preview HTML (no email, no shown record)
  GET /run/<name>?dry=1&json=1 — preview as JSON (with sourceStats)
  GET /health              — list registered digests