zeta2: Add minimal prompt for fine-tuned models (#42691)

1. Add `--prompt-format=minimal` that matches single-sentence
instructions used in fine-tuned models (specifically, in `1028-*` and
`1029-*` models)

2. Use separate configs for agentic context search model and edit
prediction model. This is useful when running a fine-tuned EP model, but
we still want to run vanilla model for context retrieval.

3. `zeta2-exp` is a symlink to the same-named Baseten deployment. This
model can be redeployed and updated without having to update the
deployment id.

4. Print scores as a compact table

Release Notes:

- N/A

---------

Co-authored-by: Piotr Osiewicz <piotr@zed.dev>

crates/cloud_llm_client/src/predict_edits_v3.rs

@@ -76,6 +76,8 @@ pub enum PromptFormat {
     OldTextNewText,
     /// Prompt format intended for use via zeta_cli
     OnlySnippets,
+    /// One-sentence instructions used in fine-tuned models
+    Minimal,
 }
 
 impl PromptFormat {
@@ -102,6 +104,7 @@ impl std::fmt::Display for PromptFormat {
             PromptFormat::OnlySnippets => write!(f, "Only Snippets"),
             PromptFormat::NumLinesUniDiff => write!(f, "Numbered Lines / Unified Diff"),
             PromptFormat::OldTextNewText => write!(f, "Old Text / New Text"),
+            PromptFormat::Minimal => write!(f, "Minimal"),
         }
     }
 }