codex: update model/effort and refresh system skills

.codex/skills/.system/skill-installer/scripts/list-skills.py

@@ -54,8 +54,7 @@ def _list_skills(repo: str, path: str, ref: str) -> list[str]:
     except urllib.error.HTTPError as exc:
         if exc.code == 404:
             raise ListError(
-                "Skills path not found: "
-                f"https://github.com/{repo}/tree/{ref}/{path}"
+                f"Skills path not found: https://github.com/{repo}/tree/{ref}/{path}"
             ) from exc
         raise ListError(f"Failed to fetch skills: HTTP {exc.code}") from exc
     data = json.loads(payload.decode("utf-8"))