style: rustfmt the four files the repo-less mission fix touched

Found while removing .github/workflows/ci.yml: three of the four files in that
change were unformatted, and four of the diffs were newly introduced (the new
prompt tests and the tool_preamble format! call). Formatting only the files that
change already touched — a repo-wide `cargo fmt` would be 63 files of unrelated
churn and belongs in its own commit.

Mechanical; `cargo test -p cm-api --lib` stays at 322 passed.

Co-Authored-By: Claude Opus 5 <[email protected]>

crates/cm-api/src/mission_outputs.rs

@@ -280,7 +280,11 @@ async fn register_empty_marker(
 /// the end of the turn (`microvm_executor` writes them over
 /// `mission_workspace::checkout_path`). Asking docker for a VM mission's files
 /// would query a container that never existed.
-async fn collect_into(mission_id: Uuid, dest: &Path, runtime_kind: &str) -> Result<Vec<PathBuf>, String> {
+async fn collect_into(
+    mission_id: Uuid,
+    dest: &Path,
+    runtime_kind: &str,
+) -> Result<Vec<PathBuf>, String> {
     // A stale copy from an earlier attempt would be registered as this pass's
     // output — the same "captured a tree nobody wrote" shape capture avoids.
     let _ = std::fs::remove_dir_all(dest);
@@ -308,8 +312,7 @@ async fn collect_into(mission_id: Uuid, dest: &Path, runtime_kind: &str) -> Resu
 /// shell-out, and this runs as the server's own uid against its own directory.
 fn copy_tree(src: &Path, dest: &Path) -> Result<(), String> {
     std::fs::create_dir_all(dest).map_err(|e| format!("create {}: {e}", dest.display()))?;
-    let entries =
-        std::fs::read_dir(src).map_err(|e| format!("read {}: {e}", src.display()))?;
+    let entries = std::fs::read_dir(src).map_err(|e| format!("read {}: {e}", src.display()))?;
     for entry in entries.flatten() {
         let from = entry.path();
         let to = dest.join(entry.file_name());
@@ -466,17 +469,15 @@ mod tests {
 
         // ...and the traversal shape this guards against is not, once resolved.
         let escaped = root.join("..").join("..").join("etc/passwd");
-        let normalised: PathBuf = escaped
-            .components()
-            .fold(PathBuf::new(), |mut acc, c| {
-                match c {
-                    std::path::Component::ParentDir => {
-                        acc.pop();
-                    }
-                    other => acc.push(other),
+        let normalised: PathBuf = escaped.components().fold(PathBuf::new(), |mut acc, c| {
+            match c {
+                std::path::Component::ParentDir => {
+                    acc.pop();
                 }
-                acc
-            });
+                other => acc.push(other),
+            }
+            acc
+        });
         assert!(
             !normalised.starts_with(&root),
             "a traversal must not resolve back inside the outputs root: {normalised:?}"