skip @reboot line for cron

api/scrape_schedule.py

@@ -62,13 +62,18 @@ def discover_cron_expr(command_hint: str, *, archive: bool) -> Optional[str]:
 
     ``command_hint`` is a substring identifying the scrape command (e.g.
     "scraper.py"); ``archive`` picks the "--archive" line vs. the plain one.
-    Returns None if the crontab can't be read or no line matches.
+    Each scrape typically has two crontab lines - an "@reboot" one and a
+    timed one; "@reboot" isn't a recurring schedule (croniter can't compute
+    a next run from it), so it's skipped in favor of the timed line.
+    Returns None if the crontab can't be read or no timed line matches.
     """
     for line in _read_crontab_lines():
         parsed = _parse_crontab_line(line)
         if parsed is None:
             continue
         schedule, command = parsed
+        if schedule.lower() == "@reboot":
+            continue
         if command_hint not in command:
             continue
         if ("--archive" in command) != archive: