chore: 上线前优化 — 清理调试日志/启用组件按需注入/补全组件声明

- 移除全项目 34 处调试 console.* 输出
- project.config.json: minified true、uploadWithSourceMap false、启用 lazyCodeLoading(requiredComponents 组件按需注入)
- pages/records/records.json 补全 ui-skeleton 组件声明(此前漏声明,WXML 已使用)
- 删除根目录残留 preview-buttons.html

pages/leaderboard/leaderboard.js

@@ -138,7 +138,6 @@ Page({
       // local data silently. No toast here: empty day-leaderboard is
       // normal (user didn't train today), and a toast would mislead
       // them into thinking the cloud is broken.
-      console.warn('[leaderboard] cloud function failed, using local fallback:', err)
       if (seq !== this._fetchSeq) { if (cb) cb(); return }
       // 已有缓存秒显时后台刷新失败:保持旧数据,不打断用户;仅无缓存才走本地兜底。
       if (cached && cached.rankedList) {