fix: normalize repeat<=0 to None to prevent cron jobs deleting after first run (#2612)

fix: normalize repeat<=0 to None — cron jobs deleted after first run when LLM passes -1

tools/cronjob_tools.py

@@ -266,8 +266,10 @@ def cronjob(
             if base_url is not None:
                 updates["base_url"] = _normalize_optional_job_value(base_url, strip_trailing_slash=True)
             if repeat is not None:
+                # Normalize: treat 0 or negative as None (infinite)
+                normalized_repeat = None if repeat <= 0 else repeat
                 repeat_state = dict(job.get("repeat") or {})
-                repeat_state["times"] = repeat
+                repeat_state["times"] = normalized_repeat
                 updates["repeat"] = repeat_state
             if schedule is not None:
                 parsed_schedule = parse_schedule(schedule)