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.wxml

@@ -7,7 +7,7 @@
     </view>
     <view class="profile-row">
       <button class="avatar-btn" open-type="chooseAvatar" bindchooseavatar="onChooseAvatar">
-        <image class="avatar-img" src="{{avatarUrl || icons.peopleFill}}" mode="aspectFit"></image>
+        <image class="avatar-img {{avatarUrl ? 'has-avatar' : ''}}" src="{{avatarUrl || icons.peopleFill}}" mode="{{avatarUrl ? 'aspectFill' : 'aspectFit'}}"></image>
         <view class="avatar-overlay">
           <text>点击设置</text>
         </view>
@@ -39,17 +39,18 @@
       <image class="section-icon" src="{{icons.skinFill}}" mode="aspectFit"></image>
       <text class="section-title">配色方案</text>
     </view>
-    <view class="theme-list">
+    <view class="theme-cards">
       <view
-        class="theme-item {{currentThemeId === item.id ? 'active' : ''}}"
+        class="theme-card {{currentThemeId === item.id ? 'active' : ''}}"
         wx:for="{{themes}}"
         wx:key="id"
         data-id="{{item.id}}"
         bindtap="onSelectTheme"
       >
-        <view class="theme-color-dot" style="background: {{item.primary}};"></view>
-        <text class="theme-name">{{item.name}}</text>
-        <image class="theme-check-img" wx:if="{{currentThemeId === item.id}}" src="{{icons.check}}" mode="aspectFit"></image>
+        <view class="theme-card-swatch" style="background: linear-gradient(135deg, {{item.primary}}, {{item.primaryLight}});">
+          <image class="theme-card-check" wx:if="{{currentThemeId === item.id}}" src="{{icons.checkWhite}}" mode="aspectFit"></image>
+        </view>
+        <text class="theme-card-name {{currentThemeId === item.id ? 'active' : ''}}">{{item.name}}</text>
       </view>
     </view>
   </ui-card>