Add a clear button to the date picker

`clearable` empties a date, or both ends of a range, closes an open
picker and hands focus back to the field, as the time picker's does.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

resources/views/showcase/sections/pickers.blade.php

@@ -3,7 +3,7 @@
         'docked' => <<<'BLADE'
             <div class="grid w-full gap-6 md:grid-cols-2" x-data="{ expires: '{{ now()->addWeek()->format('Y-m-d') }}', starts: null }">
                 <div class="grid content-start gap-4">
-                    <x-datepicker label="Expires on" x-model="expires" hint="Type a date or pick one" />
+                    <x-datepicker label="Expires on" clearable x-model="expires" hint="Type a date or pick one" />
                     <p class="type-body-sm text-on-surface-variant">Bound value: <code x-text="JSON.stringify(expires)"></code></p>
                 </div>