feat: 训练完成后首页 streak 卡片高亮 3 秒

timer 记录保存时写 _last_train_at 时间戳,index onShow 检测
< 10s 的标记则触发 just-completed class,卡片脉冲 2 次 + 主题色
边框 + 阴影,3 秒后自动淡出。让'完成训练'的反馈在首页也可见。

pages/index/index.js

@@ -41,9 +41,35 @@ Page({
     if (this._firstShow) {
       this._firstShow = false
       this.refresh()
+      this._checkFreshTrain()
       return
     }
     this.refresh()
+    this._checkFreshTrain()
+  },
+
+  /**
+   * If user just returned from completing a training, briefly highlight
+   * the "今日已完成" badge so the success feels tangible. The flag is
+   * timestamped; older than 10s is treated as stale (e.g. user reopened
+   * the app later).
+   */
+  _checkFreshTrain() {
+    try {
+      const at = wx.getStorageSync('_last_train_at')
+      if (!at) return
+      const age = Date.now() - at
+      if (age < 0 || age > 10 * 1000) {
+        wx.removeStorageSync('_last_train_at')
+        return
+      }
+      wx.removeStorageSync('_last_train_at')
+      this.setData({ justCompleted: true })
+      if (this._justCompletedTimer) clearTimeout(this._justCompletedTimer)
+      this._justCompletedTimer = setTimeout(() => {
+        this.setData({ justCompleted: false })
+      }, 3000)
+    } catch (e) {}
   },
 
   onPullDownRefresh() {