Add support for UDS in codex --remote

[etraut-openai]

Why

Added support for UDS connections in codex --remote.

TUI also now connects to local app-server using UDS by default if it is running and set to listen to UDS connection.

What Changed

• Introduced RemoteAppServerEndpoint with WebSocket and UnixSocket variants.
• Reused the existing JSON-RPC-over-WebSocket protocol over either a TCP WebSocket stream or a UDS stream.
• Updated codex --remote to accept ws://host:port, wss://host:port, unix://, and unix://PATH.
• Kept --remote-auth-token-env restricted to wss:// and loopback ws:// remotes.
• Added a fast TUI startup probe for the default daemon socket, falling back to the embedded app server when the daemon is absent or unresponsive.

Verification

• Manually verified that the updated remote flow works.
• Added coverage for UDS remote round trips, WebSocket auth headers, auth-token transport policy, remote address parsing, and missing-daemon fallback.
• Ran focused remote test coverage locally.

[chatgpt-codex-connector]

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