planReminders plans each reminder at a time of its own of an open task,
whatever its date, under an ID of its own; the notification says
"Reminder" for a task without a time. The task's sheet always has its
reminders' row: those before its time where it has one, those at a time
of their own each with its remove button and "Remind at a time" (a day,
then a time), the permission asked as a first one is chosen. The date
sheet sets a duration once there is a time (none, 15 minutes to 4
hours, as Todoist's), a time cleared taking it with it. Recorded as
ADR 0033, D18 (the developer's, 3 Nov 2026).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>