feat: clarify proxy and add LAN access toggle

scripts/next-with-lan-access.mjs

@@ -0,0 +1,48 @@
+#!/usr/bin/env node
+
+import { spawn } from 'node:child_process';
+
+const mode = process.argv[2];
+const forwardedArgs = process.argv.slice(3);
+const validModes = new Set(['dev', 'start']);
+
+if (!validModes.has(mode)) {
+  console.error('Usage: node scripts/next-with-lan-access.mjs <dev|start> [next args...]');
+  process.exit(1);
+}
+
+function isTruthyEnv(value) {
+  if (!value) {
+    return false;
+  }
+
+  return ['1', 'true', 'yes', 'y', 'on', 'enabled', 'enable'].includes(
+    value.trim().toLowerCase()
+  );
+}
+
+const lanAccessEnabled = isTruthyEnv(
+  process.env.ALLOW_LAN_ACCESS ?? process.env.NEXT_PUBLIC_ALLOW_LAN_ACCESS
+);
+const hostname = process.env.HOSTNAME || process.env.NEXT_HOSTNAME || (lanAccessEnabled ? '0.0.0.0' : 'localhost');
+const args = [mode, '--port', process.env.PORT || '3000'];
+
+if (hostname) {
+  args.push('--hostname', hostname);
+}
+
+args.push(...forwardedArgs);
+
+const child = spawn('next', args, {
+  stdio: 'inherit',
+  shell: process.platform === 'win32',
+});
+
+child.on('exit', (code, signal) => {
+  if (signal) {
+    process.kill(process.pid, signal);
+    return;
+  }
+
+  process.exit(code ?? 0);
+});