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/NavigationTest.php

@@ -647,7 +647,10 @@ it('reads expanded while a modal rail is open over the page, and collapsed once
  * Closes a rail with the given script and reports whether, sampling every few ms in the page
  * itself, it was ever caught part-way: the whole close in one round trip, since a separate
  * `script` and `assertScript` apiece already take as long as the 200ms exit (see ContainmentTest's
- * scrim fades).
+ * scrim fades). Called after slowMotion(), so the panel's own close — on the emphasized-accelerate
+ * easing, which stays close to its start for a good part of its run — still needs a couple of
+ * seconds of that stretched exit before its position has moved the couple of pixels `$partWay`
+ * looks for; 2000ms (400 × 5ms) covers that with room to spare, short of the full exit ending.
  */
 function caughtMidClose(mixed $page, string $close, string $partWay): bool
 {
@@ -655,7 +658,7 @@ function caughtMidClose(mixed $page, string $close, string $partWay): bool
         (async () => {
             {$close}
 
-            for (let i = 0; i < 60; i++) {
+            for (let i = 0; i < 400; i++) {
                 if ({$partWay}) return true
                 await new Promise((resolve) => setTimeout(resolve, 5))
             }
@@ -686,6 +689,8 @@ it('slides the compact rail out on close, rather than making it vanish', functio
         ->assertScript(RAIL.".hasAttribute('data-md-open')")
         ->assertScript(settled(RAIL_PANEL).' && Math.round('.RAIL_PANEL.'.getBoundingClientRect().left) === 0');
 
+    slowMotion($page);
+
     expect(caughtMidClose($page, "document.querySelector('[data-md-navigation-rail-scrim]').click()", slidingOut(RAIL_PANEL)))->toBeTrue();
 
     $page->assertScript('getComputedStyle('.RAIL_PANEL.").display === 'none'")
@@ -704,6 +709,8 @@ it('slides a rail that hides when collapsed out on close, rather than making it
         ->assertScript("{$rail}.hasAttribute('data-md-open')")
         ->assertScript(settled($panel)." && Math.round({$panel}.getBoundingClientRect().left) === 0 && Math.round({$panel}.getBoundingClientRect().width) === 256");
 
+    slowMotion($page);
+
     expect(caughtMidClose($page, "{$rail}.querySelector(':scope > [data-md-navigation-rail-scrim]').click()", slidingOut($panel)))->toBeTrue();
 
     $page->assertScript("getComputedStyle({$panel}).display === 'none'")
@@ -721,6 +728,8 @@ it('fades a modal rail\'s scrim out on close while the rail stands collapsed in
 
     $fading = "(getComputedStyle({$scrim}).display !== 'none' && parseFloat(getComputedStyle({$scrim}).opacity) > 0.02 && parseFloat(getComputedStyle({$scrim}).opacity) < 0.98)";
 
+    slowMotion($page);
+
     expect(caughtMidClose($page, "{$scrim}.click()", $fading))->toBeTrue();
 
     // The panel goes straight back into the layout: only the scrim was over the page.