M8: HTTP driver (framework-agnostic handler + HttpKVDriver client) passing conformance end-to-end

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Qxbkp4tA7G5SCWjzWuxmE

test/http/node-server.ts

@@ -0,0 +1,36 @@
+import { createServer, type IncomingHttpHeaders } from 'node:http'
+import type { AddressInfo } from 'node:net'
+
+/** Serves a `Request → Response` handler over a real socket (test helper). */
+export async function serve(handler: (req: Request) => Promise<Response>): Promise<{ url: string; close: () => Promise<void> }> {
+  const server = createServer(async (req, res) => {
+    const chunks: Buffer[] = []
+    for await (const c of req) chunks.push(c as Buffer)
+    const headers = Object.entries(req.headers as IncomingHttpHeaders).flatMap(([k, v]) => (v === undefined ? [] : [[k, String(v)] as [string, string]]))
+    const request = new Request(`http://localhost${req.url}`, {
+      method: req.method,
+      headers,
+      body: req.method === 'GET' || req.method === 'HEAD' ? undefined : Buffer.concat(chunks),
+    })
+    const response = await handler(request)
+    res.writeHead(response.status, Object.fromEntries(response.headers))
+    if (!response.body) return void res.end()
+    const reader = response.body.getReader()
+    res.on('close', () => void reader.cancel().catch(() => {}))
+    try {
+      for (;;) {
+        const { done, value } = await reader.read()
+        if (done) break
+        res.write(value)
+      }
+    } finally {
+      res.end()
+    }
+  })
+  await new Promise<void>((resolve) => server.listen(0, '127.0.0.1', resolve))
+  const { port } = server.address() as AddressInfo
+  return {
+    url: `http://127.0.0.1:${port}`,
+    close: () => new Promise((resolve) => (server.closeAllConnections(), server.close(() => resolve()))),
+  }
+}