Catch an exit half-way on a slow machine, not only on a fast one

The browser suite passes on every engine here and fails on the runner,
which takes three times as long: each failing test triggers a close and
then samples for an in-between state — a rail part-way out, a scrim
part-way faded, a menu's exit copy part-way sunk — and a starved runner
takes its one sample after the 150-650ms exit has already finished.

So the tests that assert *that* something animates now stretch every
motion duration token to three seconds first (`slowMotion()`, beside
`ready()` in tests/Pest.php; ActionsTest's own copy of it goes). The two
polling helpers grew their budget to match: the rail panel and the sheet
slide on emphasized-accelerate, which is under 1% of its travel at a
quarter of the way through, so a 300ms window no longer reached the
threshold once the exit itself was three seconds long.

The two full-screen date picker tests waited for a resize through
click()'s own retry, which ate the whole 15s budget on Firefox; they now
wait for the new width and a settled document first. The bottom sheet's
preset test waits for its entry to finish before pressing the grip.

`hold()` in search.js reads the view's animations a frame after the
closed state, as the rail's settle() does, but one frame is not always
enough: an engine that starts them on its next tick shows none, and the
full-screen layout would end at once, mid-exit. An empty list is now
asked again on the following frame.

Feature 1159 passed. Browser 299 passed on Chrome, Firefox and WebKit,
and again on WebKit under ten spinning cores.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/Browser/DatepickerTest.php

@@ -506,6 +506,10 @@ it('opens the range picker full screen below 600px and grows its month list both
 
     $page = dateProbe()
         ->resize(390, 800)
+        // Explicit, not implicit: the resize's own reflow can still be under way when the click
+        // that follows fires, which is what made this time out on a loaded runner — the toggle's
+        // box kept moving under the click rather than the click itself being slow.
+        ->assertScript('window.innerWidth === 390 && document.documentElement.getAnimations({ subtree: true }).length === 0')
         ->click('[aria-controls="trip-field-picker"][data-md-datepicker-toggle]')
         ->assertScript("{$picker}.dataset.mdPresentation === 'full'")
         ->assertScript("{$picker}.matches(':modal')")
@@ -552,6 +556,7 @@ it('closes the full-screen range picker from its app bar close button without ke
 
     dateProbe()
         ->resize(390, 800)
+        ->assertScript('window.innerWidth === 390 && document.documentElement.getAnimations({ subtree: true }).length === 0')
         ->click('[aria-controls="trip-field-picker"][data-md-datepicker-toggle]')
         ->click(day('trip-field', '2026-09-20'))
         ->click('#trip-field-picker [data-md-datepicker-close]')