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/index/index.wxml

@@ -10,17 +10,17 @@
   </view>
 
   <!-- 连续打卡卡片 -->
-  <ui-card variant="in" class="{{justCompleted ? 'just-completed' : ''}}">
+  <ui-card variant="gradient in" class="{{justCompleted ? 'just-completed' : ''}}">
     <view class="header-card">
       <view class="streak-section">
-        <image class="streak-icon" src="{{icons.hotFill}}" mode="aspectFit"></image>
+        <image class="streak-icon" src="{{icons.hotWhite}}" mode="aspectFit"></image>
         <text class="streak-num">{{streakCount}}</text>
         <text class="streak-label">连续打卡</text>
       </view>
       <view class="divider"></view>
       <view class="plan-info">
         <view class="plan-badge">
-          <image class="plan-badge-icon" src="{{icons.formFill}}" mode="aspectFit"></image>
+          <image class="plan-badge-icon" src="{{icons.formWhite}}" mode="aspectFit"></image>
           <text class="plan-badge-text">{{planName}}</text>
         </view>
         <view class="progress-bar-wrap">
@@ -44,7 +44,7 @@
       </view>
       <view class="target-display">
         <view class="target-ring">
-          <text class="target-time">{{todayTargetText}}</text>
+          <text class="target-time" style="font-size: {{targetTimeFontSize}}rpx;">{{todayTargetText}}</text>
         </view>
         <text class="target-unit">平板支撑</text>
       </view>
@@ -70,7 +70,7 @@
       size="xl"
       block
       text="{{todayDone ? '再次训练' : '开始训练'}}"
-      icon-src="{{icons.playFill}}"
+      icon-src="{{icons.playWhite}}"
       bindtap="onStartTrain"
     ></ui-btn>