Add buttons, menus and the rest of M3 Expressive's actions

<x-button> (label buttons, icon buttons and toggles in five sizes, with
filled, tonal, outlined, elevated and text variants in any colour role),
<x-tooltip>, <x-menu> with items, groups and separators, <x-button-group>,
<x-group> as a connected button group, <x-split-button>, <x-fab>,
<x-fab-menu> and <x-loading>. Sizes, colours and shapes come from
androidx Compose Material 3's tokens; the loading indicator ports its
Morph into SVG + SMIL.

Menus follow WAI-ARIA's menu button pattern on popovers placed by CSS
anchor positioning. Browser tests run in Chromium, Firefox and WebKit.
The showcase fetches the icon names on demand: inlined, they tripped
Pest's test server into HTTP 431s under Firefox.

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

src/Support/SvgFile.php

@@ -45,6 +45,14 @@ class SvgFile
         return static::render($path, $attributes);
     }
 
+    /**
+     * M3 Expressive's loading indicator: the morphing, rotating shape, or the shape at rest.
+     */
+    public static function loadingIndicator(bool $animated, ComponentAttributeBag $attributes): HtmlString
+    {
+        return static::render(static::directory('svg/loading-indicator/'.($animated ? 'indeterminate' : 'static').'.svg'), $attributes);
+    }
+
     /**
      * The names of every Material Symbol the package ships.
      *