chore: gitignore scratch file _run_tests.py (cron artifact, not project code)

Author: Coding-Dev-Tools

.gitignore

@@ -73,5 +73,8 @@ research/
 fixtures/generated/
 .ruff_cache/
 
+# Scratch/debug files (cron artifacts)
+_run_tests.py
+
 # Added by release-prep
 node_modules