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>
Executable translation of docs/use-cases/summarize_new_video.feature: captioned
video is summarized and delivered to the store sink; no-transcript video is
skipped with reason "no transcript" and no delivery. Drives the engine through
fake adapters (no live YouTube/brain). Intentionally RED until the engine is
implemented — this is the swarm's target.