Key the views on M3's window size classes, not Tailwind's

Plan step 15. Every `sm:`/`md:`/`lg:`/`xl:` in the components, the showcase
(sections, layout, shell) and the pagination and error views becomes the M3
window size class the audits' breakpoint maps prescribe: the full-screen
dialog, the FAB, the snackbar's width, `radio inline`, the section picker and
the page numbers move from 640px to `medium` (600px, M3's compact boundary,
N-07 / C-07 / IN-28); `button responsive` moves from 1024px to `expanded`
(840px); `section-nav`'s grid-to-row switch from 1280px to `large` (1200px,
N-07); and `drawer pane` from 1280px to `expanded`, where M3 shows two panes
for list-detail (C-07). The pane's default width is now 360dp, M3's fixed
supporting pane at expanded.

Showcase example grids take two columns from `medium` and three or more from
`expanded`; the showcase's own theme picker swaps at `expanded`, the nearest
class boundary to the 768px it used (no M3 rule applies to it).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/views/showcase/sections/timepickers.blade.php

@@ -1,7 +1,7 @@
 @php
     $examples = [
         '12 and 24 hours, outlined and filled' => <<<'BLADE'
-            <div class="grid w-full gap-6 md:grid-cols-2">
+            <div class="grid w-full gap-6 medium:grid-cols-2">
                 <div class="grid content-start gap-4">
                     <x-timepicker label="Meeting starts" value="09:30" hint="The locale's clock" />
                     <x-timepicker label="Pick-up" value="17:15" format="12" icon="local_shipping" clearable />
@@ -16,7 +16,7 @@
             </div>
             BLADE,
         'Steps and limits' => <<<'BLADE'
-            <div class="grid w-full gap-6 md:grid-cols-2">
+            <div class="grid w-full gap-6 medium:grid-cols-2">
                 <div class="grid content-start gap-4">
                     <x-timepicker label="Appointment" value="10:00" format="24" step="15" min="08:00" max="17:30" hint="Quarter hours from 08:00 to 17:30" />
                     <x-timepicker label="Night shift starts" value="23:00" format="24" min="22:00" max="06:00" hint="From 22:00, across midnight, to 06:00" />