refactor: replace print with string concatenation and convert "\n" to newlines in JSON output

Co-authored-by: aider (o3) <aider@aider.chat>

scripts/jsonl_pretty_print.py

@@ -50,9 +50,12 @@ def pretty_print_jsonl(path: Path, indent: int) -> None:
                 obj = json.loads(line)
             except json.JSONDecodeError as exc:
                 sys.exit(f"JSON decode error on line {idx}: {exc}")  # fail fast
-            # Dump the pretty JSON followed by a newline separator
-            print(json.dumps(obj, indent=indent, ensure_ascii=False, sort_keys=True))
-            print()  # blank line between records for readability
+            # Build pretty JSON string, convert literal "\n" sequences to real newlines,
+            # and emit a blank line between records for readability.
+            pretty = json.dumps(obj, indent=indent, ensure_ascii=False, sort_keys=True)
+            pretty = pretty.replace("\\n", "\n")
+            sys.stdout.write(pretty)
+            sys.stdout.write("\n\n")
 
 
 def main() -> None: