feat(image-cache): 新增图片本地缓存并全站接入

引入 cached-image 组件与 image-cache 工具，实现签名 URL 稳定 key 剥离、downloadFile 落盘及 TTL/LRU 清理，替换 11 个页面与 clothes-card 共 22 处网络图片渲染点，减少 CDN 重复流量。

miniprogram/pages/closet-share-create/closet-share-create.json

@@ -1,6 +1,7 @@
 {
   "usingComponents": {
     "navigation-bar": "/components/navigation-bar/navigation-bar",
+    "cached-image": "/components/cached-image/cached-image",
     "clothes-card": "/components/clothes-card/clothes-card",
     "v2-overlay": "/components/v2-overlay/index"
   }

miniprogram/pages/closet-share-create/closet-share-create.wxml

@@ -95,7 +95,7 @@
     <view class="csc-preview">
       <view class="csc-preview-hd">
         <view class="csc-av">
-          <image wx:if="{{avatar}}" class="pic" src="{{avatar}}" mode="aspectFill" />
+          <cached-image wx:if="{{avatar}}" class="pic" src="{{avatar}}" mode="aspectFill" />
           <view wx:else class="icon icon-user"></view>
         </view>
         <text class="csc-preview-n">{{nickname}} 向你分享了 {{selectedCount || '全部'}} 件衣物</text>