fix: 13项数据存储与排行榜修复

致命修复:
- leaderboard: 日榜日期比较改用 dateOnly() 替代严格全等
- plan: 计划天数计算日期比较改用 dateOnly()
- cloud: pullAll 添加 orderBy('updatedAt','desc') 确保取最新文档避免数据丢失

严重修复:
- cloud: 新增 cancelPendingPush() 防止清除数据后被延迟推送复活
- settings: _doClearData 补充 user_profile 清除, 先取消推送再清除
- app: 云端同步改为时间戳比对策略, 支持跨设备拉取
- app: _restoreFromCloud 增加空数据保护和 profile 恢复
- storage: 记录ID改用时间戳+自增计数器确保唯一性

中等修复:
- cloud: init/_fetchOpenid 日志升级, 新增 syncStatus getter
- leaderboard云函数: 添加90天活跃过滤减少全表扫描
- storage: validateStreak 增加lastDate无记录时的通用修复
- leaderboard页面: 云函数失败时Toast提示用户而非静默降级

轻微修复:
- timer: onUnload 添加 voice.destroy() 释放音频上下文
- records: onLongPressDelete 委托给 onDeleteRecord 消除重复代码

Co-Authored-By: Claude <noreply@anthropic.com>

pages/leaderboard/leaderboard.js

@@ -64,8 +64,11 @@ Page({
     }).then(res => {
       this._applyResult(res.result || {})
       if (cb) cb()
-    }).catch(() => {
-      // Cloud function not deployed — fall back to local data
+    }).catch((err) => {
+      // Cloud function not deployed or network error — fall back to
+      // local data but let the user know the leaderboard is degraded.
+      console.warn('[leaderboard] cloud function failed, using local fallback:', err)
+      wx.showToast({ title: '云端榜单暂不可用', icon: 'none', duration: 2000 })
       this._applyLocal()
       if (cb) cb()
     })
@@ -102,7 +105,7 @@ Page({
     let duration = 0
     let sessions = 0
     allRecords.forEach(r => {
-      if (period === 'day' && r.date === today) { duration += r.duration; sessions++ }
+      if (period === 'day' && util.dateOnly(r.date) === util.dateOnly(today)) { duration += r.duration; sessions++ }
       if (period === 'month' && r.date.startsWith(thisMonth)) { duration += r.duration; sessions++ }
       if (period === 'year' && r.date.startsWith(thisYear)) { duration += r.duration; sessions++ }
     })