Move alert configuration normalization, activation migration, global-disable cleanup, active-alert reevaluation, and threshold override cloning into internal/alerts/config_runtime.go.
Record config_runtime.go as the alert config runtime owner in the alerts subsystem contract and add an activation-state preservation characterization test.
Proof: go test ./internal/alerts/... -count=1
Proof: go test ./internal/api -run Alert -count=1
rcourtman