Give the account-menu avatar a state layer

The trigger had the focus ring but no hover and no pressed feedback at all,
where every comparable trigger in the library carries `state-layer` and M3 asks
for two visual indicators per state. An avatar image sits behind the layer, so
the wash shows over a photograph too.
Plan: docs/plans/material-3-alignment.md, step 21 (navigation N-15).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Feature/Components/AppBarTest.php

@@ -146,8 +146,9 @@ it('opens an account menu from the initials of a name', function () {
     expect($html)
         ->toContain('aria-label="Account"')
         ->toContain('data-account-menu')
-        // The 40px avatar reaches 48px, and nothing clips the pseudo-target (N-01).
-        ->toContain('touch-target')
+        // The 40px avatar reaches 48px, and nothing clips the pseudo-target (N-01); the trigger
+        // has a hover and a pressed state like every other trigger in the library (N-15).
+        ->toContain('state-layer touch-target focus-ring')
         ->not->toContain('overflow-hidden')
         ->toMatch('/>\s*AM\s*<\/button>/')
         ->toContain('anna@example.com')
@@ -155,6 +156,6 @@ it('opens an account menu from the initials of a name', function () {
         ->toContain('data-account-theme')
         ->toContain('Sign out')
         ->and((string) $this->blade('<x-account-menu avatar="/anna.jpg" :theme="false" />'))
-        ->toContain('<img src="/anna.jpg" alt="" class="size-full rounded-corner-full object-cover" />')
+        ->toContain('<img src="/anna.jpg" alt="" class="relative -z-20 size-full rounded-corner-full object-cover" />')
         ->not->toContain('data-account-theme');
 });