优化刷盘轮询，修复优先队列数量错误

crawler/crawler.go

@@ -246,12 +246,14 @@ func (c *Crawler) runPriorityWorker() {
 			// 将子链接加入优先队列（保持优先级）
 			if len(hrefs) > 0 {
 				c.priorityChildrenMu.Lock()
+				added := 0
 				for _, child := range hrefs {
 					if !c.isVisited(child) {
 						c.priorityChildren = append(c.priorityChildren, child)
+						added++
 					}
 				}
-				IncrementPriorityChildren(int64(len(hrefs)))
+				IncrementPriorityChildren(int64(added))
 				c.priorityChildrenMu.Unlock()
 			}