v2.1.1 — trial escape hatch & check-in clarity

Closes out the pre-design-review polish round.

UX

• Blocked start is now actionable — starting a food while another is under observation names the active trial and offers a one-tap 취소하고 시작 (with 닫기 to dismiss). If the observation window elapsed while the alert was open, the finished trial is auto-closed as safe instead of cancelled.
• 테스트 취소 asks first — cancelling an in-progress trial now shows a confirmation dialog before discarding observation days.
• Check-in done-state teaches its cadence — after the daily 이상 없음 tap: ✓ 이상 없음 기록됨 · 오후 2:30 + 하루 한 번이면 충분해요.

Hardening

• cancelTrial can no longer overwrite a finished safe/reacted outcome via a stale id — the UPDATE is guarded by outcome IS NULL, with a regression test asserting the generated SQL (proven to fail on the unguarded code).

Gates: TypeScript strict clean · Jest 43/43 · CI green.