Scroll a menu that is too long for the window

The popover was fit-content with overflow visible, so a long menu ran past the
edge of the top layer, where the page's own scrolling cannot reach it. It now
caps at 18rem — less on a short window — and scrolls, as M3's menu behaviour
asks, and the keyboard brings the item it moves to into view. Plan step 11,
actions.md ACT-04.

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

tests/Feature/Components/MenuTest.php

@@ -23,6 +23,12 @@ it('opens a popover menu from its trigger', function () {
         ->toContain('[position-area:bottom_span-right]');
 });
 
+it('scrolls a menu too long for the window instead of running off it', function () {
+    expect((string) $this->blade('<x-menu><x-slot:trigger><button>x</button></x-slot:trigger></x-menu>'))
+        ->toContain('max-h-[min(18rem,calc(100dvh-2rem))] overflow-y-auto')
+        ->not->toContain('overflow-visible');
+});
+
 it('opens at the position asked for, in the vibrant colours on request', function () {
     $html = (string) $this->blade('<x-menu position="top-end" vibrant><x-slot:trigger><button>x</button></x-slot:trigger></x-menu>');