feat: add codeserver dev profile

NEXT_DEV_PROFILE=codeserver wires basePath, assetPrefix, and
allowedDevOrigins from CODESERVER_HOST/PORT in .env.local. Use
/absproxy/{port} so code-server preserves the path prefix and Next's
basePath matches the incoming request.

Run with `npm run dev:codeserver` and access via
https://<host>/absproxy/<port>/.

.env.example

@@ -0,0 +1,2 @@
+CODESERVER_HOST=your-codeserver.example.com
+CODESERVER_PORT=3000

.gitignore

@@ -2,3 +2,6 @@
 node_modules/
 .next/
 out/
+.env.local
+.env*.local
+tsconfig.tsbuildinfo

next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+import "./.next/dev/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

next.config.ts

@@ -1,10 +1,32 @@
 import type { NextConfig } from "next";
 
 const isProd = process.env.NODE_ENV === "production";
+const isCodeserver = process.env.NEXT_DEV_PROFILE === "codeserver";
+
+// In dev under code-server's reverse proxy, basePath/assetPrefix must match
+// the proxy URL so links, assets, and the HMR socket all resolve.
+// Use /absproxy/{port} (NOT /proxy/{port}) — /proxy strips the prefix before
+// forwarding; /absproxy preserves it so basePath matches the incoming request.
+// CODESERVER_HOST and CODESERVER_PORT are loaded from .env.local by Next.
+function codeserverConfig() {
+  const host = process.env.CODESERVER_HOST;
+  if (!host) {
+    throw new Error(
+      "CODESERVER_HOST is required when NEXT_DEV_PROFILE=codeserver (set it in .env.local)"
+    );
+  }
+  const port = process.env.CODESERVER_PORT ?? "3000";
+  return { basePath: `/absproxy/${port}`, allowedDevOrigins: [host] };
+}
+
+const cs = isCodeserver ? codeserverConfig() : null;
+const basePath = cs?.basePath ?? (isProd ? "/loto" : "");
 
 const nextConfig: NextConfig = {
   output: "export",
-  basePath: isProd ? "/loto" : "",
+  basePath,
+  assetPrefix: basePath || undefined,
+  ...(cs?.allowedDevOrigins ? { allowedDevOrigins: cs.allowedDevOrigins } : {}),
 };
 
 export default nextConfig;

package.json

@@ -4,6 +4,7 @@
   "private": true,
   "scripts": {
     "dev": "next dev",
+    "dev:codeserver": "NEXT_DEV_PROFILE=codeserver next dev -H 0.0.0.0",
     "build": "next build",
     "start": "next start",
     "lint": "eslint"