refactor：拆分 API 路由与请求校验，统一 final 类和代码风格

app/Http/Requests/Admin/AdminLoginRequest.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Http\Requests\Admin;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+/**
+ * 管理员登录请求。
+ *
+ * @see LoginController
+ */
+final class AdminLoginRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * @return array<string, array<int, mixed>>
+     */
+    public function rules(): array
+    {
+        return [
+            'account' => ['required', 'string', 'min:2', 'max:64', 'regex:/^[a-zA-Z0-9._-]+$/u'],
+            'password' => ['required', 'string', 'max:256'],
+            'captcha_key' => ['required', 'string', 'uuid'],
+            'captcha_code' => ['required', 'string', 'max:32'],
+        ];
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function attributes(): array
+    {
+        return [
+            'account' => 'account',
+            'password' => 'password',
+            'captcha_key' => 'captcha_key',
+            'captcha_code' => 'captcha_code',
+        ];
+    }
+}