feat: install and configure Inertia.js with React

- Install inertia-laravel, @inertiajs/react, react, @vitejs/plugin-react
- Add HandleInertiaRequests middleware registered in web group
- Create Inertia root template (resources/views/app.blade.php)
- Add React entry point and page components (resources/js/)
- Add Inertia demo route (/inertia-test)
- HomeController reverted to Blade (index page stays original)
- Remove inertia-test2 test route

app/Http/Middleware/HandleInertiaRequests.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Illuminate\Http\Request;
+use Inertia\Middleware;
+
+class HandleInertiaRequests extends Middleware
+{
+    protected $rootView = 'app';
+
+    public function version(Request $request): ?string
+    {
+        return parent::version($request);
+    }
+
+    public function share(Request $request): array
+    {
+        return [
+            ...parent::share($request),
+            'avatarImager' => setting('avatar_imager'),
+        ];
+    }
+}