mara wanted one place for everything that fires at a future time.
The QU3U3D R3M1ND3RS section moves out of the SYST3M tab and
lands at the bottom of the SCH3DUL3S tab, below QU3U3D SCH3DUL3S.
Pure layout change — refreshReminders() and /api/reminders
unchanged; the section just lives under a different parent now.
Reminders don't contribute to the SCH3DUL3S pill count (kept as
"active schedules" only — reminders are self-scheduled and high
cardinality; adding them would make the pill noisy).
docs/web-ui.md picks up a SCH3DUL3S tab section (the previous
docs lumped the schedules subsection under SYST3M, but the tab
has been separate since #459); reminders subsection follows
schedules in the same tab.