feat: 重构事件总线为可实例化架构并发布 1.3.0

- 新增 IShrinkEventBus、ShrinkEventBusBuilder 与 ShrinkEventBusInstance，支持独立 bus、异常策略、启动开关、类型校验和按 phase 派发
- 新增 SubscribeEvent 可释放订阅句柄与订阅快照接口，保留 EventBus 静态门面并委托到默认实例
- 重构监听列表为父子事件链共享锁与快照缓存，支持父事件监听子事件、跨父子数字优先级归并和防御性快照拷贝
- 优化 EventBase 元数据缓存、懒生成 EventId、派发快照挂接与对象池双重归还保护，移除旧 EventCache 热路径
- 恢复本地 ILPostProcessor 兜底并生成静态订阅注册表，避免共享 CodeGen 覆盖外程序集自动注册失效
- 改进事件查看器、Benchmark、README 与 CHANGELOG，并新增 Dispatch/Priority/Registration/Subscription 测试覆盖核心行为

BREAKING CHANGE: 移除 EventBase.GetListenerList()，int 数字优先级重载不再提供默认值，数字优先级 0 现在映射为 NORMAL。

Runtime/EventCloneUtility.cs

@@ -18,8 +18,9 @@ namespace ShrinkEventBus
                 throw new InvalidOperationException(
                     $"Cannot clone event type {source.GetType().FullName}. A public parameterless constructor is required.");
 
+            // 先固化 EventId，让克隆与原事件共享同一个派发标识
+            _ = source.EventId;
             CopyFields(source, clone);
-            CopyListenerSnapshot(source, clone);
             clone.ReleaseAction = null;
             clone.IsInPool = false;
             return clone;
@@ -32,16 +33,6 @@ namespace ShrinkEventBus
                 fields[i].SetValue(target, fields[i].GetValue(source));
         }
 
-        private static void CopyListenerSnapshot(EventBase source, EventBase target)
-        {
-            var targetListeners = target.GetListenerList();
-            targetListeners.Clear();
-
-            var sourceHandlers = source.GetListenerList().GetHandlers();
-            for (var i = 0; i < sourceHandlers.Length; i++)
-                targetListeners.Add(sourceHandlers[i]);
-        }
-
         private static FieldInfo[] GetCopyableFields(Type type)
         {
             lock (CacheLock)
@@ -77,8 +68,7 @@ namespace ShrinkEventBus
 
         private static bool ShouldSkipField(FieldInfo field)
         {
-            return field.Name is "_listenerList"
-                or "<ReleaseAction>k__BackingField"
+            return field.Name is "<ReleaseAction>k__BackingField"
                 or "<IsInPool>k__BackingField";
         }
     }