ProcessNewVideos walks a user's subscriptions and processes each newly seen video. Two remaining .feature scenarios are now covered: a channel the user is not subscribed to is never surfaced (so never processed), and a video already processed in this engine's lifetime is not summarized twice. Dedup is in-memory and per-user; durable cross-restart dedup stays the store's concern (no new port), per docs/data-model.md. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>