OpenAI o3-pro model unusable in Zed due to Responses API

[jvmncs]

The new o3-pro model from OpenAI is only available in their newer, stateful Responses API, and not in the Chat Completions API that Zed uses for OpenAI models. This feature request is to expand the scope of Zed's OpenAI client to support usage of the Responses API so that o3-pro can be used in Zed.

[tigeryy2]

FYI I got o3-pro to work via openrouter, but only in minimal mode...tool use breaks it, although I might've configured it wrong since none of the o1, o3, etc models work for me via openrouter.