Add new streaming events for shell command execution and output

Introduce multiple new events to stream shell command additions, deltas, completions, and incremental output content during tool calls. These events include details such as command indexes, output indexes, deltas of stdout/stderr, and support for WebSocket streaming by providing stream IDs when available. Beta versions of these events are also added for multi-agent contexts.

OpenAI-API-Ref-Source-Revision: 971322