End-state of plan 2: operator can schedule one-off reminders via the
Telegram menu wizard, attach text + optional media (photo/video/doc),
and the bot fires them on time to a chosen group. Failed sends retry
with backoff. Run history captured in the DB.
Out of scope (deferred to follow-ups):
- Recurring reminders (RRULE)
- Multi-group / multi-part messages beyond text+1 media
- Run history view in menu
- Web dashboard (plan 3)
9 tasks covering pg-boss client, reminder CRUD helpers, sender refactor
(media), Telegram media ingest, fire-reminder handler, wizard state,
menu views, callback wiring, and end-to-end verification.