Windows: append helper dir to PATH (split from #5579; no env var changes)

codex-cli/bin/codex.js

@@ -73,9 +73,10 @@ const binaryPath = path.join(archRoot, "codex", codexBinaryName);
 function getUpdatedPath(newDirs) {
   const pathSep = process.platform === "win32" ? ";" : ":";
   const existingPath = process.env.PATH || "";
+  // Preserve caller PATH precedence by appending any additional dirs.
   const updatedPath = [
-    ...newDirs,
     ...existingPath.split(pathSep).filter(Boolean),
+    ...newDirs,
   ].join(pathSep);
   return updatedPath;
 }

codex-rs/arg0/src/lib.rs

@@ -179,9 +179,11 @@ fn prepend_path_entry_for_apply_patch() -> std::io::Result<TempDir> {
     const PATH_SEPARATOR: &str = ";";
 
     let path_element = path.display();
+    // Append our temp dir to PATH rather than prepending to avoid
+    // disturbing user PATH ordering (e.g., virtualenvs, shims).
     let updated_path_env_var = match std::env::var("PATH") {
         Ok(existing_path) => {
-            format!("{path_element}{PATH_SEPARATOR}{existing_path}")
+            format!("{existing_path}{PATH_SEPARATOR}{path_element}")
         }
         Err(_) => {
             format!("{path_element}")