Add push$ to Collection; make Container listen for retroactive blueprint changes

src/di/decorator/injection.ts

@@ -166,6 +166,7 @@ export const Singleton = (name?: string): ClassDecorator => {
                 ...(name ? { name } : {}),
             }
 
+            logIfDebugging('extollo.di.singleton', 'Registering singleton target:', target, 'injectionType:', injectionType)
             Reflect.defineMetadata(DEPENDENCY_KEYS_SERVICE_TYPE_KEY, injectionType, target)
             Injectable()(target)