chore: 修复 clippy 错误（loop never loops → if-let）并应用自动修复

src/queue/message_queue.rs

@@ -265,8 +265,8 @@ impl MessageQueue {
     /// - 该渠道还有消息 → 放回 pending 尾部
     pub fn dequeue(&mut self) -> Option<PipelineMessage> {
         while let Some(ch) = self.pending.pop_front() {
-            if let Some(q) = self.queues.get_mut(&ch) {
-                if let Some(item) = q.pop_front() {
+            if let Some(q) = self.queues.get_mut(&ch)
+                && let Some(item) = q.pop_front() {
                     if !q.is_empty() {
                         self.pending.push_back(ch);
                     } else {
@@ -274,7 +274,6 @@ impl MessageQueue {
                     }
                     return Some(item);
                 }
-            }
             self.queues.remove(&ch);
         }
         None
@@ -290,7 +289,7 @@ impl MessageQueue {
 
     #[allow(dead_code)]
     pub fn has_pending(&self, ch: &ChannelId) -> bool {
-        self.queues.get(ch).map_or(false, |q| !q.is_empty())
+        self.queues.get(ch).is_some_and(|q| !q.is_empty())
     }
 
     #[allow(dead_code)]