Draw the split button without Tailwind

Plan step 36. <x-split-button> renders data-md-split-button and
data-md-size on the pair and data-md-split on its halves. split-button.css
draws SplitButton*Tokens' shape — full outer corners, inner corners that
grow under the finger, the trailing half round while its menu is open —
the narrower leading padding and 48px trailing half at xs and sm, and the
chevron's own size, nudge and turn on the standard scheme. groups.css is
empty and leaves tailwind.css.

The actions browser test follows data-md-split and data-md-button-group,
and gains the owed tests for a connected segment's 48px edge and a
button group's single-required and multi selection.

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

tests/Feature/Components/ActionStylesheetsTest.php

@@ -17,6 +17,7 @@ dataset('action components', [
     'button',
     'group',
     'button-group',
+    'split-button',
 ]);
 
 it('draws the component from a stylesheet shaped like every package stylesheet', function (string $name) {
@@ -37,8 +38,9 @@ it('imports the stylesheet of every component its view renders', function (strin
     preg_match_all('/<x-livewire-material::([a-z-]+)/', File::get(__DIR__."/../../../resources/views/components/{$name}.blade.php"), $tags);
 
     $rendered = collect($tags[1])->unique()
-        // A component still written for Tailwind has no stylesheet of its own to import yet.
-        ->filter(fn (string $tag): bool => is_file(ComponentStylesheet::path($tag)))
+        // A component still written for Tailwind has no stylesheet of its own to import yet; its
+        // old stylesheet, if it has one, lives in tailwind.css without the layer statement.
+        ->filter(fn (string $tag): bool => is_file(ComponentStylesheet::path($tag)) && str_contains(File::get(ComponentStylesheet::path($tag)), '@layer material.components'))
         ->map(fn (string $tag): string => "./{$tag}.css")
         ->values()
         ->all();