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

tests/Feature/ShowcaseTest.php

@@ -1,5 +1,7 @@
 <?php
 
+use NoNameWeb\LivewireMaterial\Support\SvgFile;
+
 /**
  * Reboot the application with the showcase switched on or off. The routes are mounted
  * while the provider boots, so the flag has to be in the environment before that.
@@ -42,3 +44,10 @@ it('answers 404 for a symbol or style that does not exist', function () {
     $this->get('/material/symbols/outlined/not_a_symbol_at_all.svg')->assertNotFound();
     $this->get('/material/symbols/sharp/favorite.svg')->assertNotFound();
 });
+
+it('lists the symbol names for the icon search', function () {
+    $this->getJson('/material/symbols.json')
+        ->assertOk()
+        ->assertJsonFragment(['calendar_month'])
+        ->assertJsonCount(count(SvgFile::symbolNames()));
+});