Zahan Malkani 536f86e5cc Support attaching to existing realtime calls (#39876) ...

## Why

Clients that create and negotiate realtime calls themselves need Codex to join
those calls without creating another call or overwriting the client-owned
session configuration.

## What changed

- Add the `existingCall` transport to `thread/realtime/start`, accepting a
  client-provided `callId` and optional `realtimeSessionId`.
- Attach Codex over the call's sideband WebSocket without SDP negotiation or a
  session update, and reconnect that sideband while preserving transcript
  state.
- Default existing calls to realtime v1, support v1 and v3, and reject v2 or
  options that would reconfigure the client-owned session.
- Encode call IDs as a single URL path segment for v3 sideband connections.

## Testing

Add protocol, app-server, core, reconnection, authentication-header, and URL
encoding coverage for existing-call attachments.

GitOrigin-RevId: 2046b70566f98efa55381bb1e461ea3cc68256c5

2026-08-21 06:41:28 +00:00

..

schema

Support attaching to existing realtime calls (#39876)

2026-08-21 06:41:28 +00:00

scripts

Precompute app-server protocol exports (#36212)

2026-07-30 19:47:30 +00:00

src

Support attaching to existing realtime calls (#39876)

2026-08-21 06:41:28 +00:00

BUILD.bazel

Precompute app-server protocol exports (#36212)

2026-07-30 19:47:30 +00:00

Cargo.toml

Extract persisted history types into a dedicated crate (#37871)

2026-08-10 19:26:52 +00:00