Rebuild: the coordinator stops on SIGTERM

It waited for every chunk in flight, and a connection the server held
back (after killed coordinators left sessions open) waits up to the
10-minute reply timeout: it never seemed to stop. It now waits at most
15 s, then closes all connections, busy ones too; the greeting and login
time out after 30 s. And run() ends with terminate(), as edge:node does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/nntp/xover_client.ts

@@ -67,7 +67,8 @@ export class XoverClient {
       ? tls.connect({ host: options.host, port: options.port, servername: options.servername || options.host })
       : net.connect({ host: options.host, port: options.port })
     const client = new XoverClient(sock, options.timeoutMs ?? 120_000)
-    sock.setTimeout(client.timeoutMs)
+    // The greeting and login are short: a server holding a connection back (too many open) fails it in 30 s, not timeoutMs.
+    sock.setTimeout(Math.min(client.timeoutMs, 30_000))
     try {
       await client.expect(await client.line(), ['200', '201'])
       if (options.user) {