Feature#614

Labels for monitors

Tag monitors with key/value labels, filter the dashboard by label, and emit labels as OTel resource attributes.

Labels give you a lightweight way to group monitors by team, environment, customer, or anything else. Set them on the monitor edit page, in YAML, or via the CLI — they show up on dashboard rows, filter the monitor list, and emit as OTel resource attributes so downstream dashboards can slice by the same dimension.