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>

commands/coordinator_run.ts

@@ -11,6 +11,7 @@ const TICK_MS = 2000
 const PLAN_EVERY_MS = 60 * 60 * 1000
 const MERGE_EVERY_MS = 60 * 1000
 const MERGE_BUDGET_MS = 30 * 1000
+const STOP_WAIT_MS = 15 * 1000
 
 /**
  * The coordinator's background work (REBUILD.md, part 1): the prefetcher,
@@ -30,6 +31,7 @@ export default class CoordinatorRun extends BaseCommand {
     const done = new Promise<void>((resolve) => (stopped = resolve))
     // bin/console turns SIGTERM into app.terminate: wait for the spooling in flight first.
     this.app.terminating(async () => {
+      this.logger.info('Stopping: waiting for the chunks in flight.')
       stopping = true
       prefetcher.stop()
       await done
@@ -83,8 +85,13 @@ export default class CoordinatorRun extends BaseCommand {
       await sleep(TICK_MS)
     }
     await prefetching
-    while (prefetcher.active > 0) await sleep(200)
+    // The chunks in flight, for at most STOP_WAIT_MS (a connection the server holds back can take minutes); then closed.
+    const waitUntil = Date.now() + STOP_WAIT_MS
+    while (prefetcher.active > 0 && Date.now() < waitUntil) await sleep(200)
+    if (prefetcher.active > 0) this.logger.info(`Closing ${prefetcher.active} connections still fetching.`)
     await NntpPool.close()
+    this.logger.info('Coordinator stopped.')
     stopped!()
+    await this.terminate()
   }
 }