feat(motor): 序列每步新增绿色「单发」按钮，支持仅发送该步动作一次

js/motor/main.js

@@ -1997,6 +1997,7 @@ const seq = {
   round: 1,             /* 当前轮（1 起） */
   stepIdx: 0,           /* 当前步索引 */
   statusText: "未运行",
+  singleIdx: null,      /* 正在单发的步骤索引，null = 无单发在途 */
 };
 const seqListEl = $("#seqList");
 const seqStartBtn = $("#seqStartBtn");
@@ -2069,6 +2070,9 @@ function renderSeqList() {
           <input class="seq-num seq-hold" data-f="holdMs" type="number" value="${s.holdMs}" min="0" max="600000" step="100" aria-label="步骤 ${i + 1} 保持时间 ms" />
           <span class="seq-hold-unit">ms</span>
           <div class="seq-ops">
+            <button data-op="sendOne" title="单发本步（仅发送这一步的全部电机动作，不推进序列）" class="seq-send-one">
+              <svg width="13" height="13" viewBox="0 0 14 14" fill="none" aria-hidden="true"><path d="M4.5 2.8 11 7l-6.5 4.2z" fill="currentColor"/></svg>
+            </button>
             <button data-op="addAction" title="本步添加电机动作（复制最后一个动作）">
               <svg width="13" height="13" viewBox="0 0 14 14" fill="none" aria-hidden="true"><path d="M7 2.5v9M2.5 7h9" stroke="currentColor" stroke-width="1.5" stroke-linecap="round"/></svg>
             </button>
@@ -2118,8 +2122,10 @@ function renderSeqList() {
 
 function updateSeqUi() {
   const running = seq.running;
+  const sendingIdx = seq.singleIdx;
   seqStartBtn.textContent = running ? "■ 停止序列" : "▶ 开始序列";
   seqStartBtn.classList.toggle("btn-primary", running);
+  seqStartBtn.disabled = !running && sendingIdx != null;
   const st = $("#seqStatus");
   if (st) {
     if (running) {
@@ -2127,6 +2133,9 @@ function updateSeqUi() {
       const cnt = cs ? cs.actions.length : 0;
       st.textContent = `运行中 · 步骤 ${seq.stepIdx + 1}/${seq.steps.length} (${cnt} 电机) · 第 ${seq.round} 轮`;
       st.classList.add("on");
+    } else if (sendingIdx != null) {
+      st.textContent = `单发步骤 ${sendingIdx + 1}…`;
+      st.classList.add("on");
     } else {
       st.textContent = seq.statusText || `未运行 · ${seq.steps.length} 步`;
       st.classList.remove("on");
@@ -2134,7 +2143,9 @@ function updateSeqUi() {
   }
   seqListEl.classList.toggle("seq-locked", running);
   seqListEl.querySelectorAll(".seq-step").forEach((row) => {
-    row.classList.toggle("current", running && parseInt(row.dataset.idx, 10) === seq.stepIdx);
+    const idx = parseInt(row.dataset.idx, 10);
+    row.classList.toggle("current", running && idx === seq.stepIdx);
+    row.classList.toggle("sending", !running && sendingIdx === idx);
   });
   seqLoopsInput.disabled = running;
   $("#seqAddBtn").disabled = running;
@@ -2179,6 +2190,10 @@ seqListEl.addEventListener("click", (e) => {
   const step = seq.steps[i];
   if (!step) return;
   const op = btn.dataset.op;
+  if (op === "sendOne") {
+    sendSeqStepOnce(i);
+    return;
+  }
   if (op === "up" && i > 0) {
     const t = seq.steps[i]; seq.steps[i] = seq.steps[i - 1]; seq.steps[i - 1] = t;
   } else if (op === "down" && i < seq.steps.length - 1) {
@@ -2231,6 +2246,46 @@ seqStartBtn.addEventListener("click", () => {
   startSeq();
 });
 
+/* 单发一步：只把该步的全部动作经一次 sendBurst 近同时下发，不循环、不推进步骤、不等 holdMs。
+ * 与序列运行互斥（运行中按钮被 .seq-locked 屏蔽），同一时刻只允许一个单发在途。 */
+async function sendSeqStepOnce(i) {
+  if (seq.running || seq.singleIdx != null) return;
+  const step = seq.steps[i];
+  if (!step || !step.actions.length) return;
+  if (!state.connected) { toast("设备未连接", "err"); return; }
+  if (inBusCooldown()) return;
+  const chBad = step.actions.find((a) => !state.chEnabled[a.ch]);
+  if (chBad) { toast(`步骤 ${i + 1} 的通道 CH${chBad.ch} 已禁用`, "err"); return; }
+
+  seq.singleIdx = i;
+  updateSeqUi();
+  const targets = step.actions.map((a) => `CH${a.ch}·N${a.node}`).join(" ");
+  const time = new Date().toLocaleTimeString("zh-CN", { hour12: false });
+  $("#sbLastSend").textContent = `最近发送: 单发步${i + 1} → ${step.actions.length} 电机 [${targets}] ${time}`;
+  try {
+    const res = await sendBurst(step.actions);
+    if (res.busy) { toast("发送通道忙，请稍后重试", "warn"); return; }
+    if (!res.ok) { toast(`步骤 ${i + 1} 发送失败：${res.desc || "未知错误"}`, "err"); return; }
+    for (const a of step.actions) {
+      state.lastSentMode.set(a.node, parseInt(a.mode, 10) || 0);
+      state.lastSentTargets.set(a.node, {
+        mode: parseInt(a.mode, 10) || 0,
+        angle: parseFloat(a.angle) || 0,
+        velocity: parseFloat(a.velocity) || 0,
+        current: parseFloat(a.current) || 0,
+        voltage: parseFloat(a.voltage) || 0,
+      });
+    }
+    state.txCount++;
+    renderNodeList();
+    seq.statusText = `已单发步骤 ${i + 1}`;
+    toast(`步骤 ${i + 1} 已单发 · ${step.actions.length} 电机 [${targets}]`, "ok");
+  } finally {
+    seq.singleIdx = null;
+    updateSeqUi();
+  }
+}
+
 function startSeq() {
   if (!state.connected) { toast("设备未连接", "err"); return; }
   if (seq.steps.length === 0) { toast("请先添加至少一个步骤", "warn"); return; }