Put the menu on M3's Expressive spacing and behaviour

Items were 44px tall with the baseline menu's 12px sides, the separator had half
its 8dp padding, a disabled item was skipped by the keyboard entirely, a chosen
item was told by colour and shape alone, and the list simply faded in place. Now:
48px rows with 16px either side, an 8px separator, disabled items focusable but
never activatable, a trailing check on a selected item, and an enter-exit that
scales the list out of the corner nearest its trigger — the scale on the spatial
spring, the fade on the effects one. Plan step 18, actions.md ACT-11, ACT-12,
ACT-13, ACT-26, ACT-27, ACT-28.

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

resources/views/components/menu-group.blade.php

@@ -3,7 +3,7 @@
 @props(['label'])
 
 <div role="group" aria-label="{{ $label }}" {{ $attributes->class('py-1 first:pt-0 last:pb-0') }}>
-    <div aria-hidden="true" class="px-3 pt-2 pb-1 type-label-lg text-on-surface-variant">{{ $label }}</div>
+    <div aria-hidden="true" class="px-4 pt-2 pb-1 type-label-lg text-on-surface-variant">{{ $label }}</div>
 
     {{ $slot }}
 </div>