refactor(音频处理): 提取音频上下文创建逻辑到独立函数

将重复的音频上下文创建逻辑提取到独立的getAudioContextInstance函数中，减少代码重复并统一音频上下文配置

main/xiaozhi-server/test/test_page.html

@@ -230,6 +230,16 @@
         const conversationDiv = document.getElementById('conversation');
         const logContainer = document.getElementById('logContainer');
 
+        function getAudioContextInstance() {
+            if (!audioContext) {
+                audioContext = new (window.AudioContext || window.webkitAudioContext)({
+                    sampleRate: SAMPLE_RATE,
+                    latencyHint: 'interactive'
+                });
+                log('创建音频上下文，采样率: ' + SAMPLE_RATE + 'Hz', 'debug');
+            }
+            return audioContext;
+        }
 
         // 初始化可视化器
         function initVisualizer() {
@@ -306,12 +316,7 @@
             // 确保Opus解码器已初始化
             try {
                 // 确保音频上下文存在
-                if (!audioContext) {
-                    audioContext = new (window.AudioContext || window.webkitAudioContext)({
-                        sampleRate: SAMPLE_RATE
-                    });
-                    log('创建音频上下文，采样率: ' + SAMPLE_RATE + 'Hz', 'debug');
-                }
+                audioContext = getAudioContextInstance();
 
                 // 确保解码器已初始化
                 if (!opusDecoder) {
@@ -617,10 +622,7 @@
                 log('已获取麦克风访问权限', 'success');
 
                 // 创建音频上下文
-                audioContext = new (window.AudioContext || window.webkitAudioContext)({
-                    sampleRate: 16000,  // 确保采样率与服务器期望的一致
-                    latencyHint: 'interactive'
-                });
+                audioContext = getAudioContextInstance();
                 const source = audioContext.createMediaStreamSource(stream);
 
                 // 获取实际音频轨道设置
@@ -1416,12 +1418,7 @@
 
         // 创建音频处理器
         async function createAudioProcessor() {
-            if (!audioContext) {
-                audioContext = new (window.AudioContext || window.webkitAudioContext)({
-                    sampleRate: 16000,
-                    latencyHint: 'interactive'
-                });
-            }
+            audioContext = getAudioContextInstance();
 
             try {
                 // 检查是否支持AudioWorklet
@@ -1616,12 +1613,7 @@
                 });
 
                 // 创建音频上下文和分析器
-                if (!audioContext) {
-                    audioContext = new (window.AudioContext || window.webkitAudioContext)({
-                        sampleRate: 16000,
-                        latencyHint: 'interactive'
-                    });
-                }
+                audioContext = getAudioContextInstance();
 
                 // 创建音频处理器
                 const processorResult = await createAudioProcessor();