Scaffold the Livewire Material package

The skeleton for nonameweb/livewire-material: service provider and config
(unprefixed components, blade-icons' own <x-icon> switched off, an opt-in
showcase at /material), the Testbench Workbench with its Vite build, the
CSS and JS entry points applications import, the Boost guideline and skill
with a drift test, and Gitea CI running Pint, feature tests on PHP 8.4 and
8.5, and browser tests in Chrome, Firefox and Safari.

The plan moved here from SealShare: docs/plans/livewire-material.md.

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

tests/Feature/ShowcaseTest.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * 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.
+ */
+function rebootWithShowcase(bool $enabled): void
+{
+    $value = $enabled ? 'true' : 'false';
+
+    putenv("MATERIAL_SHOWCASE={$value}");
+    $_ENV['MATERIAL_SHOWCASE'] = $_SERVER['MATERIAL_SHOWCASE'] = $value;
+
+    test()->refreshApplication();
+}
+
+afterEach(function () {
+    rebootWithShowcase(true);
+});
+
+it('mounts the showcase when enabled', function () {
+    $this->withoutVite()
+        ->get('/material')
+        ->assertOk()
+        ->assertSee('Livewire Material');
+});
+
+it('does not mount the showcase when disabled', function () {
+    rebootWithShowcase(false);
+
+    $this->get('/material')->assertNotFound();
+});