Scan for Tailwind breakpoints, and drive the shell by class in the browser

Plan steps 15-17's testing. `tests/Feature/BreakpointsTest.php` reads every
file under resources/views, resources/css and resources/js — showcase example
heredocs included — and fails on any Tailwind breakpoint prefix and on any
media query or `matchMedia` string at 40, 48, 64 or 80rem (or 640/768/1024/
1280px, or the 39.99rem that stood for "below 640"). Both scans were checked
against a deliberately reintroduced `sm:w-auto` and an 80rem query.

Every render test that asserted a `sm:`/`lg:`/`xl:` class now asserts the M3
class, the drawer's pane query is 52.5rem, and the theme script keeps
`data-rail-auto` through `wire:navigate`.

NavigationTest drives the shell at 599/600/839/840/1199/1200/1600 with the
expectation each class carries: the bar on a compact window, the 96px rail from
the medium class's first pixel, a standard rail collapsed through expanded whose
menu button widens it in place with no scrim, and the rail expanded to begin
with from large and at extra-large. (Not run here — the Browser suite is out of
scope for this stream.)

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

tests/Feature/Components/SelectionTest.php

@@ -59,7 +59,7 @@ it('names unbound radios after their group and checks the given value', function
     $html = (string) $this->blade('<x-radio name="theme" value="dark" inline :options="[[\'id\' => \'light\', \'name\' => \'Light\'], [\'id\' => \'dark\', \'name\' => \'Dark\']]" />');
 
     expect($html)
-        ->toContain('sm:flex')
+        ->toContain('medium:flex')
         ->and(substr_count($html, 'name="theme"'))->toBe(2)
         ->and($html)->toMatch('/value="dark"\s+checked/')
         ->not->toMatch('/value="light"\s+checked/');