Rebuild: a stopping worker notices it on keep-alive frames too

It checked only after a data frame, so a worker waiting for its range's
spool (keep-alive frames only) never stopped on SIGTERM.

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

commands/edge_node.ts

@@ -148,12 +148,12 @@ export default class EdgeNode extends BaseCommand {
       // Inflating runs on a thread-pool thread: the next chunk inflates while this one is indexed.
       let pending: { to: number; text: Promise<Buffer> } | null = null
       for await (const frame of decodeFrames(await api.stream(range.id))) {
+        if (this.stopping) break
         if (isKeepalive(frame)) continue
         const next = { to: frame.to, text: unzipAsync(frame.data) }
         next.text.catch(() => {})
         if (pending) await handle(pending)
         pending = next
-        if (this.stopping) break
       }
       if (pending && !this.stopping) await handle(pending)
       await posting