Reapply "Add app-server transport layer with websocket support" with
additional fixes from https://github.com/openai/codex/pull/11313/changes
to avoid deadlocking.
This reverts commit 47356ff83c.
## Summary
To avoid deadlocking when queues are full, we maintain separate tokio
tasks dedicated to incoming vs outgoing event handling
- split the app-server main loop into two tasks in
`run_main_with_transport`
- inbound handling (`transport_event_rx`)
- outbound handling (`outgoing_rx` + `thread_created_rx`)
- separate incoming and outgoing websocket tasks
## Validation
Integration tests, testing thoroughly e2e in codex app w/ >10 concurrent
requests
<img width="1365" height="979" alt="Screenshot 2026-02-10 at 2 54 22 PM"
src="https://github.com/user-attachments/assets/47ca2c13-f322-4e5c-bedd-25859cbdc45f"
/>
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Co-authored-by: jif-oai <jif@openai.com>