fix: 修复头像存储、日历详情数据与弹窗定位问题

- settings: 补上缺失的 util 导入,onChooseAvatar 不再抛
  ReferenceError,头像走 data URI 永久存储主路径
- records: 日历详情改用 dateOnly 比较,修复详情永远显示 0 次/0 时长
- records: 日历详情弹窗从 ui-modal 改为普通 view + fixed,
  修复被底部 dock 遮挡/不居中;补暗黑阴影描边与滚动穿透处理

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pages/records/records.wxml

@@ -113,31 +113,37 @@
   </view>
   <!-- /hidden wrapper -->
 
-  <!-- 日期详情弹窗 -->
-  <ui-modal visible="{{showDayDetail}}" position="center" bind:close="onCloseDayDetail">
-    <view class="detail-date-row">
-      <image class="detail-icon" src="{{icons.calendarFill}}" mode="aspectFit"></image>
-      <text class="detail-date">{{dayDetail.date}}</text>
-    </view>
-    <view class="detail-grid">
-      <view class="detail-item">
-        <image class="detail-item-icon" src="{{icons.rankFill}}" mode="aspectFit"></image>
-        <text class="detail-num">{{dayDetail.sessions}}次</text>
-        <text class="detail-label">训练次数</text>
+  <!-- 日期详情弹窗:普通 view 实现,不用 ui-modal。
+       自定义组件根元素的 position: fixed 会被小程序运行时吞掉,叠加
+       .page-enter 的 transform 会让 fixed 降级相对 .container,导致弹窗
+       落到容器末尾而非视口居中。普通 view 的 fixed 100% 生效。 -->
+  <view wx:if="{{showDayDetail}}" class="day-detail-mask" catchtouchmove="onNoop">
+    <view class="day-detail-mask__bg" bindtap="onCloseDayDetail"></view>
+    <view class="day-detail-body" catchtap="onNoop">
+      <view class="detail-date-row">
+        <image class="detail-icon" src="{{icons.calendarFill}}" mode="aspectFit"></image>
+        <text class="detail-date">{{dayDetail.date}}</text>
       </view>
-      <view class="detail-item">
-        <image class="detail-item-icon" src="{{icons.timeFill}}" mode="aspectFit"></image>
-        <text class="detail-num">{{dayDetail.durationText}}</text>
-        <text class="detail-label">总时长</text>
+      <view class="detail-grid">
+        <view class="detail-item">
+          <image class="detail-item-icon" src="{{icons.rankFill}}" mode="aspectFit"></image>
+          <text class="detail-num">{{dayDetail.sessions}}次</text>
+          <text class="detail-label">训练次数</text>
+        </view>
+        <view class="detail-item">
+          <image class="detail-item-icon" src="{{icons.timeFill}}" mode="aspectFit"></image>
+          <text class="detail-num">{{dayDetail.durationText}}</text>
+          <text class="detail-label">总时长</text>
+        </view>
+        <view class="detail-item">
+          <image class="detail-item-icon" src="{{icons.hotFill}}" mode="aspectFit"></image>
+          <text class="detail-num">{{dayDetail.calories}}</text>
+          <text class="detail-label">约消耗 (千卡)</text>
+        </view>
       </view>
-      <view class="detail-item">
-        <image class="detail-item-icon" src="{{icons.hotFill}}" mode="aspectFit"></image>
-        <text class="detail-num">{{dayDetail.calories}}</text>
-        <text class="detail-label">约消耗 (千卡)</text>
+      <view class="detail-close" bindtap="onCloseDayDetail">
+        <text>关闭</text>
       </view>
     </view>
-    <view class="detail-close" bindtap="onCloseDayDetail">
-      <text>关闭</text>
-    </view>
-  </ui-modal>
+  </view>
 </view>