The app can express a window closing and a day repeating; daily.ts counts
in days and stops there. This is the arithmetic under the rung between
them.
Local wall-clock rather than milliseconds, because a reader's own event is
local throughout — a weekly reset set for 09:00 stays at 09:00 across a DST
transition, where adding 7*DAY would move it an hour and drag every later
occurrence with it. Months clamp to the last valid day rather than letting
setMonth roll 31 February into 3 March, which is the same silent shift
readerInstant already refuses on the way in.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
