feat: 单位切换按钮（Mbps / MB/s，仅影响显示，数据库仍存 Mbps）

internal/web/templates/index.html

@@ -63,8 +63,25 @@
   #startBtn:hover { transform: translateY(-1px); filter: brightness(1.08); }
   #startBtn:disabled { opacity: .55; cursor: not-allowed; transform: none; }
 
+  /* ---------- 单位切换 ---------- */
+  .toolbar { display: flex; justify-content: flex-end; margin-top: 16px; }
+  .unit-switch {
+    display: inline-flex; gap: 2px; padding: 3px;
+    background: var(--card); border: 1px solid var(--border); border-radius: 999px;
+  }
+  .unit-btn {
+    padding: 5px 16px; font-size: 13px; color: var(--muted);
+    background: transparent; border: none; border-radius: 999px;
+    cursor: pointer; transition: all .15s;
+  }
+  .unit-btn:hover { color: var(--text); }
+  .unit-btn.active {
+    color: #06121f; font-weight: 700;
+    background: linear-gradient(90deg, var(--accent1), var(--accent2));
+  }
+
   /* ---------- 统计卡片 ---------- */
-  .stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 18px; }
+  .stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 12px; }
   .stat {
     background: var(--card); border: 1px solid var(--border); border-radius: 14px;
     padding: 16px 10px; text-align: center;
@@ -160,6 +177,14 @@
       <button id="startBtn">开始测速</button>
     </section>
 
+    <!-- 单位切换 -->
+    <div class="toolbar">
+      <div class="unit-switch">
+        <button class="unit-btn active" data-unit="Mbps">Mbps</button>
+        <button class="unit-btn" data-unit="MB/s">MB/s</button>
+      </div>
+    </div>
+
     <!-- 结果统计 -->
     <section class="stats">
       <div class="stat" id="cardLatency">
@@ -221,6 +246,44 @@ const statUpload = document.getElementById('statUpload');
 let running = false;
 let gaugeMode = 'speed';   // speed | latency
 
+/* ================= 单位切换 =================
+ * 显示单位：Mbps（兆比特/秒，默认）或 MB/s（兆字节/秒 = Mbps ÷ 8）
+ * 数据库始终以 Mbps 存储，仅影响显示。
+ */
+let unit = localStorage.getItem('speedtest_unit') === 'MB/s' ? 'MB/s' : 'Mbps';
+let lastGaugeMbps = 0;  // 仪表盘当前速率（Mbps 原值）
+let lastResult = null;  // 最近一次测速结果（Mbps 原值）
+
+function fmtSpeed(mbps) {
+  const v = unit === 'MB/s' ? mbps / 8 : mbps;
+  return v.toFixed(2);
+}
+
+function updateUnitButtons() {
+  document.querySelectorAll('.unit-btn').forEach(b => {
+    b.classList.toggle('active', b.dataset.unit === unit);
+  });
+}
+
+// 切换单位后刷新所有速度显示（仪表盘 / 统计卡 / 排行榜）
+function refreshSpeedDisplays() {
+  if (gaugeMode === 'speed') updateGaugeSpeed(lastGaugeMbps);
+  if (lastResult) {
+    statDownload.textContent = fmtSpeed(lastResult.download);
+    statUpload.textContent = fmtSpeed(lastResult.upload);
+  }
+  loadRankings(false);
+}
+
+document.querySelectorAll('.unit-btn').forEach(b => {
+  b.addEventListener('click', () => {
+    unit = b.dataset.unit;
+    localStorage.setItem('speedtest_unit', unit);
+    updateUnitButtons();
+    refreshSpeedDisplays();
+  });
+});
+
 /* ================= 仪表盘 ================= */
 function drawGauge(frac) {
   const ctx = gauge.getContext('2d');
@@ -267,8 +330,10 @@ function speedFrac(mbps) {
 
 function updateGaugeSpeed(mbps) {
   gaugeMode = 'speed';
-  gaugeValue.textContent = (mbps >= 100 ? mbps.toFixed(0) : mbps.toFixed(1));
-  gaugeUnit.textContent = 'Mbps';
+  lastGaugeMbps = mbps;
+  const v = unit === 'MB/s' ? mbps / 8 : mbps;
+  gaugeValue.textContent = (v >= 100 ? v.toFixed(0) : v.toFixed(1));
+  gaugeUnit.textContent = unit;
   drawGauge(speedFrac(mbps));
 }
 
@@ -550,8 +615,8 @@ function renderRanking(rows) {
       '<td><span class="rank-no ' + cls + '">' + r.rank + '</span></td>' +
       '<td>' + user + (r.is_mine ? '<span class="mine-tag">我的成绩</span>' : '') + '</td>' +
       '<td class="val-la">' + r.latency_ms.toFixed(1) + ' <span class="unit-sm">ms</span></td>' +
-      '<td class="val-dl">' + r.download_mbps.toFixed(2) + ' <span class="unit-sm">Mbps</span></td>' +
-      '<td class="val-up">' + r.upload_mbps.toFixed(2) + ' <span class="unit-sm">Mbps</span></td>' +
+      '<td class="val-dl">' + fmtSpeed(r.download_mbps) + ' <span class="unit-sm">' + unit + '</span></td>' +
+      '<td class="val-up">' + fmtSpeed(r.upload_mbps) + ' <span class="unit-sm">' + unit + '</span></td>' +
       '<td class="time">' + r.created_at + '</td>' +
       '</tr>';
   }).join('');
@@ -606,14 +671,16 @@ async function runTest() {
     // 2. 下载（固定 10 秒）
     setPhase('下载测速准备中…');
     const download = await downloadTest();
-    statDownload.textContent = download.toFixed(2);
+    lastResult = { download, upload: 0 };
+    statDownload.textContent = fmtSpeed(download);
     updateGaugeSpeed(download);
     markDone(document.getElementById('cardDownload'));
 
     // 3. 上传（固定 10 秒）
     setPhase('上传测速准备中…');
     const upload = await uploadTest();
-    statUpload.textContent = upload.toFixed(2);
+    lastResult = { download, upload };
+    statUpload.textContent = fmtSpeed(upload);
     updateGaugeSpeed(upload);
     markDone(document.getElementById('cardUpload'));
 
@@ -640,6 +707,7 @@ startBtn.addEventListener('click', runTest);
 
 /* ================= 初始化 ================= */
 drawGauge(0);
+updateUnitButtons();
 updateSortHeaders();
 loadRankings(false);