rework message styling (#2877)

https://github.com/user-attachments/assets/cf07f62b-1895-44bb-b9c3-7a12032eb371

codex-rs/core/src/util.rs

@@ -1,4 +1,3 @@
-use std::path::Path;
 use std::time::Duration;
 
 use rand::Rng;
@@ -12,33 +11,3 @@ pub(crate) fn backoff(attempt: u64) -> Duration {
     let jitter = rand::rng().random_range(0.9..1.1);
     Duration::from_millis((base as f64 * jitter) as u64)
 }
-
-/// Return `true` if the project folder specified by the `Config` is inside a
-/// Git repository.
-///
-/// The check walks up the directory hierarchy looking for a `.git` file or
-/// directory (note `.git` can be a file that contains a `gitdir` entry). This
-/// approach does **not** require the `git` binary or the `git2` crate and is
-/// therefore fairly lightweight.
-///
-/// Note that this does **not** detect *work‑trees* created with
-/// `git worktree add` where the checkout lives outside the main repository
-/// directory. If you need Codex to work from such a checkout simply pass the
-/// `--allow-no-git-exec` CLI flag that disables the repo requirement.
-pub fn is_inside_git_repo(base_dir: &Path) -> bool {
-    let mut dir = base_dir.to_path_buf();
-
-    loop {
-        if dir.join(".git").exists() {
-            return true;
-        }
-
-        // Pop one component (go up one directory).  `pop` returns false when
-        // we have reached the filesystem root.
-        if !dir.pop() {
-            break;
-        }
-    }
-
-    false
-}