The transparent comma-Parse path builds failover chains via NewFailoverModel
with no options, so defaultFailoverConfig() left the observer nil and observers
only fired when a caller passed WithFailoverObserver explicitly. Add a
package-level default observer (SetFailoverObserver / DefaultFailoverObserver),
guarded by the existing defaultsMu, and seed it in defaultFailoverConfig() so
chains built transparently still notify it. An explicit WithFailoverObserver
still overrides the default per-chain. mort sets this at boot to persist
failover events.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
steve
1206261e6a