@spec create(
  ArchAstro.Client.t(),
  ArchAstro.Types.Operations.PostApiV1AiChatCompletionsStream.Input.t()
) ::
  ArchAstro.SSE.Stream.t(
    ArchAstro.Types.Operations.PostApiV1AiChatCompletionsStream.StreamEvent.t()
  )

Stream a chat completion

Streams a chat completion over Server-Sent Events. Emits thinking_delta for supported reasoning models, message_delta, message_complete, tool_call_*, tool_result, and a terminal done (or error) event. Same request shape as the non-streaming completion endpoint; the app must have the llm_calls entitlement.

Server-Sent Events stream