feat: add column visibility toggle with localStorage persistence

Add a "列设置" dropdown next to the results header that lets users
check/uncheck columns to show or hide them. Preferences persist across
page refreshes via localStorage. Also add allowedDevOrigins to
next.config.ts for LAN access.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

next.config.ts

@@ -1,7 +1,7 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  allowedDevOrigins: ["192.168.110.146"],
 };
 
 export default nextConfig;