## What changed
- Negotiate compression over TCP and local sockets with `x-codex-app-server-compression: zstd-stream-v1`. Keep JSON text messages when compression is not negotiated.
- Send compressed JSON as binary messages, retaining a separate zstd stream per direction across messages. Export reusable negotiation and codec helpers.
- Limit decompressed messages to 64 MiB and compression windows to 1 MiB. Close compressed connections on decoding errors or unexpected text messages.
- Add audit and deny ignores for the unmaintained `zvariant`, `zbus_names`, and `zvariant_derive` versions pulled in through `zbus`.
## Testing
Add codec tests for retained history, fallback, size limits, malformed data, and oversized compression windows. Add TCP and local-socket round-trip tests covering negotiation, persistent streams, and ping/pong handling, plus TCP fallback for absent or unsupported offers.
GitOrigin-RevId: 50d3861e8fe4a9c523599a5ab773bec7cb883bf2
thorvald-oai
8d9f6466ff