Use a typed escalation fallback instead of fallbackTopic

TerdutTeam spec.escalation.fallback is now {type, address}, mirroring the
server's notification channel model. CRDs regenerated.

Claude-Session: https://claude.ai/code/session_016mBLURvJoMuUEr9cB2RpUN

internal/controller/terdutteam_config.go

@@ -55,10 +55,14 @@ func buildEscalationRequest(spec *terdutv1alpha1.EscalationSpec) (tdclient.SetEs
 			Targets:        targets,
 		}
 	}
+	var fallback tdclient.NotificationTarget
+	if spec.Fallback != nil {
+		fallback = tdclient.NotificationTarget{Type: spec.Fallback.Type, Address: spec.Fallback.Address}
+	}
 	return tdclient.SetEscalationRequest{
-		RepeatCount:   spec.RepeatCount,
-		FallbackTopic: spec.FallbackTopic,
-		Levels:        levels,
+		RepeatCount: spec.RepeatCount,
+		Fallback:    fallback,
+		Levels:      levels,
 	}, nil
 }