chore(HTML): 更新 audio-visualization 部分页面，扩展频谱高频范围

HTML/audio-visualization/1.html

@@ -494,7 +494,7 @@
 
     // 模式0：频谱柱状图（居中对称 + 镜像）
     function drawSpectrum() {
-      const barCount = bufferLength / 2;
+      const barCount = bufferLength; // 使用全部频段 bin，保留高频
       const barWidth = (width * 0.8) / barCount;
       const gap = 2;
       const maxBarHeight = height * 0.35;

HTML/audio-visualization/2.html

@@ -204,7 +204,7 @@
       // 对数分布采样索引，低频更细腻
       function buildBands(bins) {
         const bands = [];
-        const minF = 2, maxF = bins * 0.72;
+        const minF = 2, maxF = bins; // 覆盖全部 bin，保留高频
         for (let i = 0; i <= BAR_COUNT; i++) {
           const t = i / BAR_COUNT;
           bands.push(Math.floor(minF * Math.pow(maxF / minF, t)));

HTML/audio-visualization/5.html

@@ -895,7 +895,7 @@ function drawFreqBars(high) {
   const gap = W / barCount * 0.4;
 
   for (let i = 0; i < barCount; i++) {
-    const freqIdx = Math.floor(i / barCount * (freqData.length * 0.6));
+    const freqIdx = Math.floor(i / barCount * (freqData.length - 1)); // 覆盖全部频段，保留高频
     const val = freqData[freqIdx] / 255;
     const barH = val * H * 0.35;
     const x = i * (barWidth + gap) + gap * 0.5;

HTML/audio-visualization/6.html

@@ -311,7 +311,7 @@
     function drawSpectrum(x, y, w, h) {
       ctx.save();
       const bars = 64;
-      const step = Math.floor(freqData.length / 2 / bars);
+      const step = Math.floor(freqData.length / bars); // 覆盖全部 bin，保留高频
       const bw = w / bars;
       if (peakHold.length !== bars) peakHold = new Array(bars).fill(0);
 

HTML/audio-visualization/7.html

@@ -360,7 +360,7 @@ function drawGrid(time) {
 function drawSkyline() {
   if (!freqArray) return;
   const binCount = analyser.frequencyBinCount;
-  const usable = Math.floor(binCount * 0.6);
+  const usable = binCount; // 覆盖全部频段，保留高频
   const barCount = 80;
   const barW = W / barCount;
   const baseY = H * 0.9;