Add plugin store feature to backend and frontend

Implemented plugin store API endpoints and types in the backend, including mock data and handlers for listing, detail, and install actions. Added plugin store page, card component, and related logic to the frontend, with navigation and categorized browsing. Updated plugin manager controller and site config to support the new plugin store functionality.

packages/napcat-webui-frontend/src/config/site.tsx

@@ -9,6 +9,7 @@ import {
   LuTerminal,
   LuZap,
   LuPackage,
+  LuStore,
 } from 'react-icons/lu';
 
 export type SiteConfig = typeof siteConfig;
@@ -65,6 +66,11 @@ export const siteConfig = {
       icon: <LuPackage className='w-5 h-5' />,
       href: '/plugins',
     },
+    {
+      label: '插件商店',
+      icon: <LuStore className='w-5 h-5' />,
+      href: '/plugin_store',
+    },
     {
       label: '系统终端',
       icon: <LuTerminal className='w-5 h-5' />,