fix(09): WR-10 keep cabana's own backend guard when it is activated twice on one application

modules/bouncer/registry.go

@@ -54,6 +54,16 @@ func (reg *Registry) Register(pluginID, name string, g any) error {
 	return nil
 }
 
+// Owner returns the plugin ID that registered the guard name. The second
+// result is false when no guard has that name.
+func (reg *Registry) Owner(name string) (string, bool) {
+	if reg == nil {
+		return "", false
+	}
+	ng, ok := reg.guards[name]
+	return ng.pluginID, ok
+}
+
 // Middleware derives an http middleware from a registered guard. Unknown
 // names fail (fail boot, mirrors surf.RegisterMiddleware's contract).
 // On Authenticate/AuthenticateCredential success: WithUser (+WithCredential