How to add monitoring to gocron scheduled jobs in Go

gocron is the most widely used job scheduling library in Go. It handles the hard parts of scheduling — cron expressions, concurrency control, timezone awareness, singleton modes — and gets out of your way. What it doesn't do is tell you when something goes wrong. The gocron v2 documentation lists a Monitor interface and a MonitorStatus interface for collecting metrics from job execution. Both entries note the same thing: "There are currently no open source implementations of the Monitor interf