Task 9b9188b8. Adds a typed client for GET /api/v1/admin/history and the History screen (ADMIN-SPEC §5): All events / Reversals / Missed chips that re-query the API, per-period On time / Completed / Missed stats, rows grouped by local day with event type, actor and on-time flag, the append-only footer strip, an inert CSV button (TODO e5133d0f) and the 92px scroll-column padding. Wires the tab into the shell. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>