feat: add form request classes for all auth controllers

app/Http/Requests/Auth/RegisterRequest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Http\Requests\Auth;
+
+use App\Models\User;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rules;
+
+class RegisterRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return (bool) config('auth-ui.features.registration');
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, array<mixed>>
+     */
+    public function rules(): array
+    {
+        return [
+            'username' => [
+                'required', 'string', 'max:255', 'alpha_dash',
+                function ($attribute, $value, $fail): void {
+                    if (User::whereRaw('LOWER(username) = ?', [strtolower($value)])->exists()) {
+                        $fail('The username has already been taken.');
+                    }
+                },
+            ],
+            'first_name' => ['required', 'string', 'max:255'],
+            'last_name' => ['required', 'string', 'max:255'],
+            'email' => ['required', 'string', 'lowercase', 'email', 'max:255', 'unique:'.User::class],
+            'password' => ['required', 'confirmed', Rules\Password::defaults()],
+        ];
+    }
+}