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/TabsTest.php

@@ -64,7 +64,7 @@ it('draws section navigation as secondary tabs and a picker', function () {
         ->toContain('aria-label="Settings"')
         ->toContain('data-section-picker')
         ->toContain('data-variant="secondary"')
-        ->toContain('sm:flex')
+        ->toContain('medium:flex')
         ->toMatch('/href="\/settings\/security"\s+data-tab\s+aria-current="page"\s+wire:navigate/')
         ->not->toMatch('/href="\/settings\/profile"\s+data-tab\s+aria-current/')
         // The picker is a menu of places: the current one is the page, not a checked choice,
@@ -80,7 +80,7 @@ it('marks the section whose url is the request\'s, and wraps many sections onto
     $items = collect(range(1, 7))->map(fn (int $n): array => ['title' => "S{$n}", 'url' => $n === 3 ? url('/') : "/s/{$n}"])->all();
 
     expect((string) $this->blade('<x-section-nav :items="$items" no-wire-navigate />', ['items' => $items]))
-        ->toContain('sm:grid sm:grid-cols-4 xl:flex')
+        ->toContain('medium:grid medium:grid-cols-4 large:flex')
         ->toMatch('/data-tab\s+aria-current="page"\s*>\s*<span data-tab-content>\s*<span class="truncate">S3/')
         ->not->toContain('wire:navigate');
 });