fix: add freeze_support to handle multiprocessing in PyInstaller builds

Ensure that helper processes spawned by multiprocessing (e.g., for HuggingFace downloads)
do not accidentally re-execute the main CLI logic when running the frozen binary.

Author: codingmoh

src/open_codex/main.py

@@ -85,4 +85,6 @@ def main():
     one_shot_mode(prompt)
 
 if __name__ == "__main__":
+    from multiprocessing import freeze_support
+    freeze_support()
     main()