Two operator-value features: evidence that shows HOW it happened, and the
one-line answer to "what happened overnight".
Evidence timeline (closes the P1-B "前中後 스냅샷 배선" follow-up):
- The ring buffer now stores per-frame head boxes, and an event captures the
frames nearest T-2.5s / T-1.0s / T-0 (server cap: 3 snapshots). A fall's
evidentiary value is in the seconds BEFORE the person hit the floor - one
end-state frame never showed how it happened.
- Each past frame is blurred with the head positions of ITS OWN moment -
blurring history with the current tick's boxes would leave a face exactly
where it actually was (PIPA).
- Right after startup the ring is short: fewer frames go out, never zero and
never duplicated. Detail view captions the sequence 이전/직전/발생 시점 by
position (offsets are edge config the server doesn't know).
24h catch-up brief:
- The events console renders one line above the stream on load - "지난 24시간
- 감지 N건 (중대 n) · 니어미스 n · 평균 대응 t · 미확인 n건 남음" - reusing
GET /api/report?days=1, with a link into /report. High-tinted when the
window held critical/high events; hidden entirely until data arrives.
Verified: pytest 235 pass (3 new: timeline selection, short-buffer dedup,
3-frame capture through run_once) / PHPUnit 138 pass + Chrome real-render
(brief line with severe tint on the console; detail page showing the
3-frame timeline with captions; no console errors).
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