fix(mobile): 流转树全览居中 + 拖拽缩放性能优化

1. fitAll() 居中修复: 内容坐标系整体对齐视口中心
   旧: mvX=0, mvY=0 (内容偏右下角)
   新: mvX = (viewportW - canvasW * scale) / 2, mvY同理

2. movable-area 显式像素高度: 替代 flex:1
   避免触摸区域计算不准确导致拖拽延迟

3. onScale 节流: rAF/setTimeout 限频 16ms
   避免 @scale 每帧触发 Vue 响应式更新

4. 新增 onChange 同步手势结束后的位置
   惯性动画结束后记录位置，下次 fitAll 参考使用

5. 添加 inertia+friction+damping 惯性动画参数

track-uniapp/src/pages/scan/components/TreeCanvas.vue

@@ -22,11 +22,12 @@
     </view>
 
     <template v-else>
-      <movable-area class="tree-movable-area">
+      <movable-area class="tree-movable-area" :style="{ width: viewportW + 'px', height: areaHeight + 'px' }">
         <movable-view class="tree-movable-view" direction="all"
           :x="mvX" :y="mvY" :scale="true" :scale-min="0.1" :scale-max="5"
           :scale-value="mvScale" :style="{ width: canvasWidth + 'px', height: canvasHeight + 'px' }"
-          @scale="onScale">
+          :inertia="true" :friction="2" :damping="40"
+          @scale="onScale" @change="onChange">
 
           <view class="canvas-inner">
             <!-- 🔧 连线层 -->
@@ -68,10 +69,15 @@ export default {
     return {
       mvX: 0, mvY: 0, mvScale: 1,
       viewportW: 375, viewportH: 600,
+      areaHeight: 500,
+      _scalePending: false,
+      _pendingScale: 1,
     };
   },
   mounted() {
     try { const info = uni.getSystemInfoSync(); this.viewportW = info.windowWidth || 375; this.viewportH = info.windowHeight || 600; } catch {}
+    // 🚀 给 movable-area 明确像素高度，避免 flex:1 导致触摸区域计算不准
+    this.areaHeight = Math.max(this.viewportH - 100, 400);
     this.$nextTick(() => this.fitAll());
   },
   computed: {
@@ -204,11 +210,30 @@ export default {
     canvasHeight() { const ns = this.treeNodes; if (!ns.length) return 400; return Math.max(...ns.map(n => n.y)) + 200; },
     fitScale() {
       if (!this.treeNodes.length) return 1;
-      return Math.max(0.1, Math.min((this.viewportW - 32) / this.canvasWidth, (this.viewportH - 100) / this.canvasHeight, 1));
+      return Math.max(0.1, Math.min((this.viewportW - 32) / this.canvasWidth, (this.areaHeight - 16) / this.canvasHeight, 1));
     }
   },
   methods: {
-    onScale(e) { if (e?.detail?.scale) this.mvScale = e.detail.scale; },
+    // 🚀 缩放事件节流：用 rAF 限频，避免每帧触发 Vue 响应式更新导致卡顿
+    onScale(e) {
+      const s = e?.detail?.scale;
+      if (!s) return;
+      this._pendingScale = s;
+      if (!this._scalePending) {
+        this._scalePending = true;
+        // uni-app 环境优先用定时器（兼容小程序），H5 用 rAF
+        const schedule = typeof requestAnimationFrame === 'function' ? requestAnimationFrame : (fn) => setTimeout(fn, 16);
+        schedule(() => {
+          this.mvScale = this._pendingScale;
+          this._scalePending = false;
+        });
+      }
+    },
+    // 🚀 手势结束后同步位置（仅记录，不回绑 :x/:y 避免干扰原生拖拽）
+    onChange(e) {
+      if (e?.detail?.x !== undefined) this.mvX = e.detail.x;
+      if (e?.detail?.y !== undefined) this.mvY = e.detail.y;
+    },
     zoomIn() { this.mvScale = Math.min(5, +(this.mvScale + 0.2).toFixed(1)); },
     handleNodeTap(node) {
       if (node.records && node.records.length > 0) {
@@ -218,7 +243,18 @@ export default {
       }
     },
     zoomOut() { this.mvScale = Math.max(0.1, +(this.mvScale - 0.2).toFixed(1)); },
-    fitAll() { this.mvScale = this.fitScale; this.mvX = 0; this.mvY = 0; },
+    // 🚀 全览居中：缩放至适配 + 主分支水平居中 + 垂直起始位置
+    fitAll() {
+      const scale = this.fitScale;
+      const canvasW = this.canvasWidth;
+      const canvasH = this.canvasHeight;
+      const viewW = this.viewportW;
+      const viewH = this.areaHeight;
+      // 内容整体在视口中居中
+      this.mvScale = scale;
+      this.mvX = (viewW - canvasW * scale) / 2;
+      this.mvY = (viewH - canvasH * scale) / 2;
+    },
     fmtDate(d) { if (!d) return ""; const dt = new Date(d); return (dt.getMonth() + 1) + '/' + dt.getDate(); },
     statusLabel(s) { const m = { PENDING: "待接收", WIP: "进行中", COMPLETED: "已完成", REJECTED: "已驳回", ARCHIVED: "已入库", CANCELED: "已撤回" }; return m[s] || s; },
     statusColor(s) { switch (s) { case "PENDING": return "s-yellow"; case "WIP": return "s-blue"; case "COMPLETED": return "s-green"; case "REJECTED": return "s-red"; case "CANCELED": return "s-canceled"; case "ARCHIVED": return "s-archived"; default: return "s-gray"; } },
@@ -243,7 +279,7 @@ export default {
 .zero-task { display: flex; flex-direction: column; align-items: center; padding: 60px 0; }
 .zero-icon { font-size: 40px; margin-bottom: 10px; }
 .zero-text { font-size: 14px; color: #9ca3af; }
-.tree-movable-area { flex: 1; width: 100%; background-color: #f0f2f5; background-image: linear-gradient(#dde1e6 1px, transparent 1px), linear-gradient(90deg, #dde1e6 1px, transparent 1px); background-size: 24px 24px; }
+.tree-movable-area { width: 100%; background-color: #f0f2f5; background-image: linear-gradient(#dde1e6 1px, transparent 1px), linear-gradient(90deg, #dde1e6 1px, transparent 1px); background-size: 24px 24px; overflow: hidden; }
 .canvas-inner { position: absolute; left: 0; top: 0; }
 
 /* 🔧 连线（禁止吞事件） */