node:http: IncomingMessage.headers is undefined (rawHeaders works) — breaks Hono/Express adapters #3272

Summary

On a node:http server, IncomingMessage.headers is undefined in a Perry-compiled binary, although req.method and req.url are correct and req.rawHeaders is fully populated. This breaks every HTTP framework that reads req.headers (Hono/Express adapters, cookie/auth parsing, host resolution).

Repro

import { createServer } from 'node:http';
const server = createServer((req, res) => {
  let out = '';
  out += 'typeof req.headers = ' + (typeof req.headers) + '\n';     // undefined
  out += 'req.method = ' + req.method + '\n';                        // GET  ✅
  out += 'req.url = ' + req.url + '\n';                              // /probe ✅
  out += 'typeof req.rawHeaders = ' + (typeof req.rawHeaders) + '\n';// object ✅
  out += 'rawHeaders = ' + JSON.stringify(req.rawHeaders) + '\n';    // ["host","127.0.0.1:3138","user-agent",...] ✅
  res.end(out);
});
server.listen(3138, '127.0.0.1', () => console.log('listening'));

$ curl -s -H 'X-Test: hi' http://127.0.0.1:3138/probe
typeof req.headers = undefined
req.method = GET
req.url = /probe
typeof req.rawHeaders = object
rawHeaders = ["host","127.0.0.1:3138","user-agent","curl/8.7.1","accept","*/*","x-test","hi"]

Expected

req.headers should be a lowercased-key object (Node semantics), e.g. { host: "127.0.0.1:3138", "user-agent": "curl/8.7.1", accept: "*/*", "x-test": "hi" }.

Workaround

Rebuild from req.rawHeaders (the flat [k,v,k,v,…] array), which is correct. But most third-party adapters read req.headers directly, so they break out of the box.

Environment

Perry 0.5.1039 (origin/main e824b66 + local fix for the unrelated querystring duplicate-fn build break), macOS arm64. node:http server via libperry_ext_http.