feat(api): add article/attachment API endpoints, admin management, and API docs

- Articles API: list/detail/create/update/delete with source-based permission control
- Attachments API: upload/list/delete with source-based permission control
- ApiKeyInfo API: query current key permissions
- Admin ApiKey management: generate/regenerate/toggle/permission settings with layui UI
- Frontend API documentation page with complete interface reference

app/api/controller/ApiKeyInfo.php

@@ -0,0 +1,33 @@
+<?php
+namespace app\api\controller;
+
+use app\BaseController;
+
+class ApiKeyInfo extends BaseController
+{
+    protected $middleware = [\app\middleware\ApiKeyAuth::class];
+
+    public function info()
+    {
+        $request = $this->request;
+
+        $can_delete_text = '不能删除';
+        if ($request->can_delete == 1) {
+            $can_delete_text = '仅删除API数据';
+        } elseif ($request->can_delete == 2) {
+            $can_delete_text = '可删除所有数据';
+        }
+
+        return json_message([
+            'admin_id' => $request->admin_id,
+            'can_write_own' => $request->can_write_own,
+            'can_write_other' => $request->can_write_other,
+            'can_delete' => $request->can_delete,
+            'permissions_text' => [
+                'can_write_own' => $request->can_write_own ? '可管理自己的数据' : '不可管理自己的数据',
+                'can_write_other' => $request->can_write_other ? '可管理后台数据' : '不可管理后台数据',
+                'can_delete' => $can_delete_text,
+            ],
+        ]);
+    }
+}