06a495cc5b normalized non-int counters but caught only TypeError/ValueError.
json.loads turns a hand-edited Infinity / -Infinity / 1e999 into float inf,
int(inf) raises OverflowError, and that escaped load_jobs, so every job
(list, tick, mark_job_run, hermes cron list) failed, not just the bad one.
Catch OverflowError (-> 0), and also clamp a negative int count, which
granted extra runs. The docs sentence now says non-negative.