zeta2: Build edit prediction prompt and process model output in client (#41870)

Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <agus@zed.dev>
Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

crates/cloud_llm_client/src/cloud_llm_client.rs

@@ -1,5 +1,4 @@
 pub mod predict_edits_v3;
-pub mod udiff;
 
 use std::str::FromStr;
 use std::sync::Arc;