Function applySubscriptionEvent

applySubscriptionEvent(
state: SubscriptionLifecycleState | undefined,
event: DomainEvent,
): SubscriptionLifecycleState
单事件推进；非法输入 fail-loud（语义见 SubscriptionLifecycleState）。
Parameters
- state: SubscriptionLifecycleState | undefined
  当前折叠态（起点为 undefined）
- event: DomainEvent
  待应用的领域事件
Returns SubscriptionLifecycleState
推进后的新折叠态
- Defined in libs/core/src/modules/subscriptions/domain/subscription-lifecycle-fold.ts:59