fix: route traceback output through Django's self.stderr

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: augustjohnson

api_v2/management/commands/compare_srd.py

@@ -345,7 +345,7 @@ def handle(self, *args, **options):
                     results[etype] = future.result()
                 except Exception as exc:
                     self.stderr.write(f"  ERROR comparing {etype}: {exc}")
-                    traceback.print_exc()
+                    self.stderr.write(traceback.format_exc())
                     failed.append(etype)
 
         if failed: