Review found the headline feature unreachable. `valid` still demanded an end
date unconditionally, while every sibling rule had been gated on
`datedWindow`. A fresh form starts with endKnown true and endDate empty, so
picking weekly hid both the field and the checkbox and left Save disabled
with nothing on screen a reader could do about it. Editing an existing event
was fine, which is why no test caught it: every static render drives the form
through `initial`, and cadenceOf never returns a preset for an event that has
an end.
So the three states that needed a click to reach are now pure functions that
do not. endStated pins exactly that case. repeatOf takes the cadence and
answers for all five, which also makes `until` surviving the preset path
provable — mutating it away previously left the suite green.
Two more from the same review. The unknown-end note keyed off the cadence, so
custom with the repeat set to never promised a countdown that would never
arrive; it keys off the rule now, which is what actually decides. And a delay
whose start and end disagree about having a time of day can never land a
whole unit from the anchor — unstatable, not merely unstated — so it says so
rather than disabling Save in silence.
"State it myself" was also a one-way door: nothing ever cleared it, so the
measured reading could not be recovered without abandoning the form.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>