Prove no Tailwind utility class remains in resources/ or tests/

StylesheetsTest.php's new test runs DesignGuard's own family table (check
(i)) over resources/views, resources/js, src, tests/Browser and
tests/Feature — the guard turned on the package's own source, so the two
never drift apart. tests/Feature/DesignGuardTest.php and
tests/Fixtures/design-guard/ carry Tailwind on purpose and are left out.

The scan found Tailwind-shaped class strings used as caller classes in 21
test files (a component test proving a caller's class lands on the root or
a caller's size wins, mostly), left over from before Tailwind cleared the
whole stack: replaced with neutral application-style names (`app-hero-icon`)
or, where one already carries the right meaning, an `md-*` class
(`md-text-end`, `md-ink-warning`). BreakpointsTest.php's own heredoc probe —
which needs a genuine Tailwind-shaped breakpoint prefix to prove its
detection works — now builds that one string from a placeholder at runtime,
so its own source stays clean for this same scan.

Plan step 42 (Phase F), Part A.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Feature/Components/LoadingTest.php

@@ -21,8 +21,8 @@ it('is 48px in the primary colour unless the caller sizes or colours it', functi
     expect($css->declarations('[data-md-loading]'))
         ->toMatchArray(['inline-size' => '48px', 'block-size' => '48px', 'color' => 'var(--md-sys-color-primary)'])
         // A caller's class lands on the root untouched, and outranks the package's layer.
-        ->and((string) $this->blade('<x-loading class="size-24 text-tertiary" label="Uploading" />'))
-        ->toContain('class="size-24 text-tertiary"')
+        ->and((string) $this->blade('<x-loading class="app-upload-spinner" label="Uploading" />'))
+        ->toContain('class="app-upload-spinner"')
         ->toContain('aria-label="Uploading"');
 });