Constant MIN_INTERVAL_SECS 

pub const MIN_INTERVAL_SECS: u64 = 5;

LOADBEARING: floor on probe interval guards against a misconfigured 0/1-second probe DOSing the host. Operator-declared intervalSeconds values below this are rounded up at the worker layer (crate::runtime::workers::probe::spawn clamps via interval_seconds.max(MIN_INTERVAL_SECS)). A weaker .max(1) floor would still let a 1-second HTTP probe issue 60 reqs/min against an operator-unintended backend.