Allow Codex App to connect to a custom app-server endpoint

What variant of Codex are you using?

App

What feature would you like to see?

I would like the Codex App to provide a user-configurable app-server connection in its Connections UI, equivalent to the CLI --remote <ADDR> option.

The connection could accept the same endpoint types supported by the CLI: unix://, ws://, and wss://, with authentication settings where applicable. Once connected, the App could use that app-server for thread listing, reading, resuming, turn operations, approvals, and notifications.

This would allow the App, CLI, and other clients to share one writer-owning app-server. Support for local and self-hosted endpoints is central to this request; official Remote Control could remain a built-in connection option.

Additional information

Paginated threads permit one app-server process to hold writer ownership. When another process owns the thread, opening it through a different app-server can fail with:

thread <thread-id> already has an active writer (code -32600)

The CLI can connect to an existing app-server:

codex app-server --listen unix:///tmp/codex.sock
codex --remote unix:///tmp/codex.sock

The App currently has no equivalent way to select that endpoint, so it can end up using a separate app-server that competes for writer ownership.

#37403 documents the resulting writer-conflict behavior. Related discussions include #33750 about sharing one app-server across connection methods and #11166, which delivered comparable endpoint support for the CLI.

Start in the App's Connections UI and trace how the CLI's --remote option reaches codex app-server; compare the existing connection paths with the documented unix://, ws://, and wss:// endpoints. Review #37403, #33750, and #11166 for writer ownership and endpoint-support context. Done means the App can configure and use a selected endpoint for the listed thread, turn, approval, and notification operations.