Bring the living docs current with the recency-bounded auto-summarize + sparse
honesty + feed IA bundle (ADR-020):
- requirements (BDD): summarize_mode.feature — auto now summarizes RECENT new
videos; added a scenario for older videos (listed, on-demand), recency note.
- architecture.md: summarization-mode + new list-surface paragraph; scheduler
diagram + two-path table + three-phase pass now show the recency pre-filter;
dropped stale "Summarize now".
- data-model.md: auto_summarize is recent-only, older on-demand.
- README.md: one-line recency note on the serve scheduler.
- ui-spec.md: appended the as-built ADR-020 row (supersedes earlier copy/sort).
- specs/{video-card-states,newest-first-ordering,scheduled-discovery}.md:
superseded/extended banners pointing at ADR-020 (kept as design records).
Docs-only; task check green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Product intent: new users get summaries of their newest videos fast while the
back-catalogue fills behind, within the shared rate gate. The background batch
currently processes in subscription/channel order, not newest-first — this spec
closes that gap (collect candidates, sort published_at DESC NULLS LAST, process
in order, gate unchanged). Also corrects the docs to describe Try-now as
onboarding prioritisation, explicitly removing the prior "looks organic to
YouTube" traffic-disguising framing — rate limiting is respected, not evaded.