Summary

• add a dedicated Discord inbound worker boundary for queued runs
• stop reusing channels.discord.eventQueue.listenerTimeout as the timeout for queued agent turns
• add explicit channels.discord.inboundWorker.runTimeoutMs config and document the new timeout split
• keep the async worker follow-up plan in docs/experiments/plans/discord-async-inbound-worker.md

Why

The current Discord path used the Carbon listener timeout as the timeout for queued background runs in message-handler.ts.

That meant a healthy queued run could be aborted just because it outlived the gateway listener budget. The failing repro test in this PR captured that mismatch.

This change separates those concerns:

• eventQueue.listenerTimeout now remains the gateway listener budget for normalization and enqueue work
• queued Discord turns now run under a worker-owned timeout instead

Changes

• src/discord/monitor/inbound-job.ts
  • add the first-pass Discord inbound job boundary and queue-key helper
• src/discord/monitor/inbound-worker.ts
  • add the in-process inbound worker queue
  • own queued-run lifecycle, abort handling, and worker timeout logging there
  • default worker timeout is 30 minutes; runTimeoutMs: 0 disables it
• src/discord/monitor/message-handler.ts
  • move queued execution behind the inbound worker
  • keep preflight and debounce logic in the handler
• src/discord/monitor/provider.ts
  • stop passing eventQueue.listenerTimeout into the message handler as a run timeout
  • pass discord.inboundWorker.runTimeoutMs explicitly instead
• config/docs
  • add channels.discord.inboundWorker.runTimeoutMs
  • clarify that channels.discord.eventQueue.listenerTimeout is only the listener budget
• tests
  • keep the queued-timeout characterization coverage
  • add coverage that listener timeout is no longer reused as the worker timeout
  • add coverage that queued runs can complete when worker timeout is disabled

Verification

• pnpm vitest src/discord/monitor/message-handler.queue.test.ts src/discord/monitor/provider.test.ts
• pnpm tsgo
• pnpm build