gpui 0.2.2 asserts on a deferred draw inside another, and every dialog,
sheet and popover draws inside one, so opening a date field in the
snooze or schedule dialog panicked, as would any list, menu or picker
opened in an overlay. primitives::raise replaces each deferred draw:
at the top it defers as before; inside something raised it leaves a
placeholder in the tree, and its layer lays it out on its own, then
draws it last. check.sh refuses gpui's deferred anywhere else.
The time dialog's rule is now times::ahead, tested for a moment
behind, now itself, a moment ahead and another zone; a gpui test picks
yesterday in the snooze dialog, sees that it has passed and that
nothing is sent, then picks two days ahead and hears that moment.