Keep cache-control merge regressions easy to review

Reflow the two long cache-control regression assertions in transform.rs so the neighboring merge cases stay rustfmt-aligned and easier to scan.

This keeps the preserved code change separate from the untracked Markdown design notes the user did not want committed.

Constraint: Exclude Markdown design files from the commit while preserving the local code change
Rejected: Include docs in the same commit | user explicitly asked to leave Markdown files out
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Treat this as a readability-only test change; do not infer runtime behavior changes from it
Tested: cargo test --manifest-path src-tauri/Cargo.toml test_anthropic_to_openai_drops_ --lib
Tested: cargo check --manifest-path src-tauri/Cargo.toml --tests
Tested: pnpm format:check
Tested: pnpm typecheck
Not-tested: Full application integration and manual flows

src-tauri/src/proxy/providers/transform.rs

@@ -670,7 +670,10 @@ mod tests {
 
         let result = anthropic_to_openai(input, None).unwrap();
         assert_eq!(result["messages"][0]["role"], "system");
-        assert_eq!(result["messages"][0]["content"], "You are Claude Code.\nBe concise.");
+        assert_eq!(
+            result["messages"][0]["content"],
+            "You are Claude Code.\nBe concise."
+        );
         assert!(result["messages"][0].get("cache_control").is_none());
     }
 
@@ -688,7 +691,10 @@ mod tests {
 
         let result = anthropic_to_openai(input, None).unwrap();
         assert_eq!(result["messages"][0]["role"], "system");
-        assert_eq!(result["messages"][0]["content"], "You are Claude Code.\nBe concise.");
+        assert_eq!(
+            result["messages"][0]["content"],
+            "You are Claude Code.\nBe concise."
+        );
         assert!(result["messages"][0].get("cache_control").is_none());
     }