feat(ui): 记录页月份联动与多项 UI 美化/修复

- records: 底部列表与月份选择器联动，新增 [本月|最近] 分段控件；标题/空态随模式切换
- leaderboard: 领奖台布局(冠军居中+皇冠)、次数标注于底座且三档水平对齐；头像 cloud:// 批量预解析提速(云函数需重新部署)
- index/timer: 主色底图标改白色变体修复隐形；目标数字按微信字体缩放补偿真机遮挡
- settings: 配色方案横滑渐变色卡；头像上传前压缩至 200px
- theme: 新增 teal 主题；暗黑背景统一对齐
- 圆形头像双保险(image 自身 border-radius)修复月/年榜方图

注: cloudfunctions/leaderboard 改动须在开发者工具重新部署才生效。

pages/settings/settings.js

@@ -194,12 +194,37 @@ Page({
    */
   async _uploadAvatar(filePath) {
     if (!cloud.enabled) throw new Error('cloud not enabled')
+    // Shrink the chosen avatar (chooseAvatar returns a full-res PNG) before
+    // upload — a 200px-wide file is tens of KB vs the original's MB, which
+    // is what lets remote avatars load in well under a second on the
+    // leaderboard. Falls back to the original file if compression is
+    // unavailable (e.g. old base lib / devtools) so upload never breaks.
+    const compressed = await this._compressAvatar(filePath)
     const cloudPath = `avatar/${Date.now()}-${Math.floor(Math.random() * 1e6)}.png`
-    const res = await wx.cloud.uploadFile({ cloudPath, filePath })
+    const res = await wx.cloud.uploadFile({ cloudPath, filePath: compressed })
     if (!res || !res.fileID) throw new Error('uploadFile returned no fileID')
     return res.fileID
   },
 
+  /**
+   * Compress an avatar temp file to ~200px wide before upload. Uses
+   * wx.compressImage (base lib 2.21.0+ honours `compressedWidth`; older
+   * libs ignore it and just apply `quality`, still a win). Resolves to the
+   * original path on any failure so the caller degrades gracefully.
+   */
+  _compressAvatar(filePath) {
+    return new Promise((resolve) => {
+      if (!wx.compressImage || !filePath) { resolve(filePath); return }
+      wx.compressImage({
+        src: filePath,
+        quality: 80,
+        compressedWidth: 200,
+        success: (res) => resolve((res && res.tempFilePath) || filePath),
+        fail: () => resolve(filePath)
+      })
+    })
+  },
+
   onNicknameBlur(e) {
     const value = (e.detail.value || '').trim()
     if (!value) return