Fix ruff lint error FURB192 by using min instead of sorted

Author: Copilot

src/gh_llm/github_api.py

@@ -1757,7 +1757,7 @@ def _find_direct_pull_request_template_via_listing(
                 candidates.append(candidate_path)
         if not candidates:
             return None
-        return sorted(candidates, key=str.casefold)[0]
+        return min(candidates, key=str.casefold)
 
     def _list_pull_request_template_directories(
         self,