chore: merge git crates (#5909)

Merge `git-apply` and `git-tooling` into `utils/`

codex-rs/chatgpt/src/apply_command.rs

@@ -59,13 +59,13 @@ pub async fn apply_diff_from_task(
 
 async fn apply_diff(diff: &str, cwd: Option<PathBuf>) -> anyhow::Result<()> {
     let cwd = cwd.unwrap_or(std::env::current_dir().unwrap_or_else(|_| std::env::temp_dir()));
-    let req = codex_git_apply::ApplyGitRequest {
+    let req = codex_git::ApplyGitRequest {
         cwd,
         diff: diff.to_string(),
         revert: false,
         preflight: false,
     };
-    let res = codex_git_apply::apply_git_patch(&req)?;
+    let res = codex_git::apply_git_patch(&req)?;
     if res.exit_code != 0 {
         anyhow::bail!(
             "Git apply failed (applied={}, skipped={}, conflicts={})\nstdout:\n{}\nstderr:\n{}",