[ks93]

Summary

• Add agents.chat_stream(...), which takes the same arguments as chat() but streams Server-Sent Events while the agent works. It sends stream: true with Accept: text/event-stream.
• It yields typed events:
  • AgentChatProgress: status updates, e.g. "Searching knowledge graph...".
  • AgentChatResponseChunk: fragments of the reply, to be concatenated as they arrive.
  • AgentChatResponse: the final, complete response (cursor, messages, action calls). Always the last event.
  • UnknownAgentChatStreamEvent: for event types the SDK doesn't know yet.
• The union is exported as AgentChatStreamEvent. The sync client gets a regular iterator through the codegen.
• chat() and chat_stream() now share a small helper that builds the request body.

A separate method is used instead of a stream flag on chat(), since a function that returns a response or an iterator depending on a flag is awkward to type, especially for the generated sync client.

The codegen adds a # type: ignore [misc] to generated iterator methods. It isn't needed here (mypy flags it as unused), so it is removed by hand, the same as for geospatial.stream_features. The codegen's verify step ignores comments, so this stays in sync.

Testing

• Unit tests for the request (stream flag, accept header), typed events in order, unknown event types, the [DONE] sentinel, multi-line data: fields, comment lines, and a stream without a trailing blank line.
• Smoke-tested against a live CDF project: 71 response chunks followed by the final AgentChatResponse with a cursor, and the joined chunks matched the final text.