Add `cloud_llm_client` crate (#35307)

This PR adds a `cloud_llm_client` crate to take the place of the
`zed_llm_client`.

Release Notes:

- N/A
b8f3a9101cMarshall Bowers committed on 7/29/2025, 11:30:45 PM· committed by GitHubparent3824751
5 files changedLine totals unavailable