feat(panel): in-panel API documentation page

New /panel/api-docs route with a one-page reference covering every
/panel/api/* endpoint (Auth, Inbounds, Server, Nodes, Custom Geo,
Backup) plus a Bearer-token primer that reads the current token and
exposes Show/Copy/Regenerate inline. Sidebar gets an API Docs entry
right after Xray; the menu label is shared via menu.apiDocs across all
13 locales.

frontend/vite.config.js

@@ -26,6 +26,8 @@ const BASE_MIGRATED_ROUTES = {
   'panel/xray/': '/xray.html',
   'panel/nodes': '/nodes.html',
   'panel/nodes/': '/nodes.html',
+  'panel/api-docs': '/api-docs.html',
+  'panel/api-docs/': '/api-docs.html',
 };
 
 let cachedBasePath = '/';
@@ -150,6 +152,7 @@ export default defineConfig({
         inbounds: path.resolve(__dirname, 'inbounds.html'),
         xray: path.resolve(__dirname, 'xray.html'),
         nodes: path.resolve(__dirname, 'nodes.html'),
+        apiDocs: path.resolve(__dirname, 'api-docs.html'),
         subpage: path.resolve(__dirname, 'subpage.html'),
       },
       output: {