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/components/navigation-bar.blade.php

@@ -1,7 +1,7 @@
 {{-- M3 Expressive's flexible navigation bar: three to five destinations at the bottom of a
      compact window.
 
-         <div class="fixed inset-x-0 bottom-0 z-30 sm:hidden">
+         <div class="fixed inset-x-0 bottom-0 z-30 medium:hidden">
              <x-navigation-bar>
                  <x-navigation-bar-item label="Inbox" icon="inbox" link="/inbox" active badge="12" />
                  <x-navigation-bar-item label="Starred" icon="star" link="/starred" />