The Remind Me dialog only offered four fixed presets, so you couldn't set a
reminder for an arbitrary time. Add a "Custom time…" option that reveals date +
time pickers (validated >= 1 minute in the future) and sets the reminder at that
absolute timestamp.
Also extract the local date/time <input> helpers (toLocalDate, toLocalTime,
parseLocalDateTime, pickerInputStyle) into a shared, unit-tested
utils/datetimeInput.ts and reuse them in ScheduleMessageModal (deduped from an
inline copy) — identical output, now covered by tests.
Documents the previously-undocumented Message Reminders feature in
LOTUS_FEATURES.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
