fix: SSE连接关闭时机提前至容器关闭最早阶段

添加@Order(Ordered.HIGHEST_PRECEDENCE)确保最高优先级执行，
在Tomcat关闭前主动断开所有SSE连接，避免阻塞应用停止

src/main/java/com/youlai/boot/message/registry/SseSessionRegistry.java

@@ -4,6 +4,8 @@ import com.youlai.boot.message.dto.OnlineUserDTO;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.context.event.ContextClosedEvent;
 import org.springframework.context.event.EventListener;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
 import org.springframework.stereotype.Component;
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
@@ -199,6 +201,7 @@ public class SseSessionRegistry {
     /**
      * 容器关闭时主动断开所有 SSE 连接，避免阻塞应用停止
      */
+    @Order(Ordered.HIGHEST_PRECEDENCE)
     @EventListener(ContextClosedEvent.class)
     public void destroy() {
         int count = emitterUserMap.size();