Fix unified exec large output regex and remove python dependency

Author: codex-bot

codex-rs/core/tests/suite/unified_exec.rs

@@ -1678,7 +1678,7 @@ PY
     let large_output = outputs.get(call_id).expect("missing large output summary");
 
     let output_text = large_output.output.replace("\r\n", "\n");
-    let truncated_pattern = r"(?s)^Total output lines: \d+\n{2,}(token token \n){5,}.*…\d+ tokens truncated….*(token token \n){5,}$";
+    let truncated_pattern = r"(?s)^Total output lines: \d+\n\n(token token \n){5,}.*…\d+ tokens truncated….*(token token \n){5,}$";
     assert_regex_match(truncated_pattern, &output_text);
 
     let original_tokens = large_output