Refs #1341
buildAlertsDiagnostic previously emitted only boolean flags (legacy
thresholds, missing cooldown/grouping window). Override keys and their
trigger values were absent, so triaging a support case where the user
suspects an override mismatch required asking them to paste
data/alerts.json from inside their container. Add an Overrides slice
that names each persisted key with its thresholds and disabled flags.
Sanitize mode in the frontend redacts the keys to override-N while
keeping thresholds visible, so a public export still shows the alert
shape without leaking instance names that may be hostnames.
rcourtman
9ac7df976f