修复语音/通话音频断续：改为持续运行的队列处理器

原实现：取出所有块精确调度 → 等播完 → 退出处理器 → 新块到达无人处理
→ 下一批启动有间隙

改为：持续运行的处理器循环，新块到达时立即调度到上一块结束时间，
消除批次间的间隙。用 nextScheduleTime 追踪精确调度位置，
防止累积延迟。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/stores/chatStore.js

@@ -554,7 +554,7 @@ export const useChatStore = defineStore('chat', () => {
           
           // 如果没有在播放，开始播放队列
           if (!isPlayingQueue.value) {
-            playAudioQueue()
+            startAudioQueueProcessor()
           }
         }
         break
@@ -991,7 +991,7 @@ export const useChatStore = defineStore('chat', () => {
           
           // 如果没有在播放，开始播放队列
           if (!isPlayingQueue.value) {
-            playAudioQueue()
+            startAudioQueueProcessor()
           }
         }
         break
@@ -1433,57 +1433,65 @@ export const useChatStore = defineStore('chat', () => {
   /**
    * 播放音频队列 - 顺序播放所有缓冲的音频片段
    */
-  async function playAudioQueue() {
-    if (isPlayingQueue.value) return
-    if (audioQueue.value.length === 0) return
+  // 持续运行的音频队列处理器
+  let audioQueueRunning = false
+  let nextScheduleTime = 0
 
+  async function startAudioQueueProcessor() {
+    if (audioQueueRunning) return
+    audioQueueRunning = true
     isPlayingQueue.value = true
     isPlaying.value = true
 
-    // 初始化AudioContext
     if (!currentAudioContext || currentAudioContext.state === 'closed') {
       currentAudioContext = new (window.AudioContext || window.webkitAudioContext)({
         sampleRate: 24000
       })
     }
-
-    // 确保 AudioContext 处于运行状态
-    await ensureAudioContext(currentAudioContext);
+    await ensureAudioContext(currentAudioContext)
+    nextScheduleTime = currentAudioContext.currentTime
 
     try {
-      // 一次性取出队列中所有音频块
-      const chunks = []
-      while (audioQueue.value.length > 0) {
-        const item = audioQueue.value.shift()
-        if (item) chunks.push(item)
-      }
+      while (audioQueueRunning) {
+        // 取出当前队列中所有块
+        const chunks = []
+        while (audioQueue.value.length > 0) {
+          const item = audioQueue.value.shift()
+          if (item) chunks.push(item)
+        }
 
-      if (chunks.length === 0) return
+        if (chunks.length === 0) {
+          // 无新块，短暂等待后继续检查
+          await new Promise(r => setTimeout(r, 20))
+          continue
+        }
 
-      // 用精确时间调度所有块，消除间隙
-      let nextStartTime = currentAudioContext.currentTime
-      let lastSource = null
+        // 确保调度时间不早于当前时间（防止累积延迟）
+        if (nextScheduleTime < currentAudioContext.currentTime) {
+          nextScheduleTime = currentAudioContext.currentTime
+        }
 
-      for (const chunk of chunks) {
-        const result = schedulePCMChunk(chunk.data, chunk.sampleRate, nextStartTime)
-        nextStartTime += result.duration
-        lastSource = result.source
-      }
-
-      // 等待最后一块播放完成
-      if (lastSource) {
-        await new Promise((resolve) => {
-          lastSource.onended = () => resolve()
-        })
+        // 精确调度每个块
+        for (const chunk of chunks) {
+          const result = schedulePCMChunk(chunk.data, chunk.sampleRate, nextScheduleTime)
+          nextScheduleTime += result.duration
+        }
       }
     } catch (error) {
-      console.error('[ChatStore] Audio queue playback error:', error)
+      console.error('[ChatStore] Audio queue processor error:', error)
     } finally {
       isPlayingQueue.value = false
       isPlaying.value = false
+      audioQueueRunning = false
     }
   }
 
+  function stopAudioQueueProcessor() {
+    audioQueueRunning = false
+    isPlayingQueue.value = false
+    isPlaying.value = false
+  }
+
   /**
    * 将 PCM 数据解码为 AudioBuffer
    */
@@ -1580,6 +1588,7 @@ export const useChatStore = defineStore('chat', () => {
    * 重置音频状态
    */
   function resetAudioState() {
+    stopAudioQueueProcessor()
     audioQueue.value = []
     isPlayingQueue.value = false
     isPlaying.value = false
@@ -1626,6 +1635,8 @@ export const useChatStore = defineStore('chat', () => {
    * 停止音频播放
    */
   function stopAudioPlayback() {
+    // 停止持续队列处理器
+    stopAudioQueueProcessor()
     // 清空音频队列
     audioQueue.value = []
     isPlayingQueue.value = false
@@ -1854,7 +1865,6 @@ export const useChatStore = defineStore('chat', () => {
     // 音频播放
     playAudio,
     playPCMAudio,
-    playAudioQueue,
     stopAudio,
     stopAudioPlayback,
     resetAudioState,