feat(fe): 社区帖子图片点击放大预览

缩略图保持网格展示，点击走 wx.previewImage 全屏预览，
可左右切换同帖多图（emoji 占位不参与）。

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

pets-fe/pages/community/community.js

@@ -132,6 +132,13 @@ Page({
   onCreatePost() {
     this.setData({ sheetType: 'createPost', sheetShow: true });
   },
+  // 点缩略图放大预览。只取 http 图（机器人帖的 emoji 占位不参与）
+  onPreviewImage(e) {
+    const { urls, cur } = e.currentTarget.dataset;
+    const list = (urls || []).filter((u) => typeof u === 'string' && u.indexOf('http') === 0);
+    if (!list.length) return;
+    wx.previewImage({ current: cur, urls: list });
+  },
   // 长按自己的帖子可删除
   onLongPressPost(e) {
     const p = this.data.posts[e.currentTarget.dataset.index];

pets-fe/pages/community/community.wxml

@@ -25,7 +25,8 @@ module.exports.isUrl = function (s) { return s && s.indexOf('http') === 0; }
     <view class="post-content">{{item.content}}</view>
     <view wx:if="{{item.images.length}}" class="photo-grid">
       <block wx:for="{{item.images}}" wx:for-item="img" wx:key="*this">
-        <image wx:if="{{im.isUrl(img)}}" class="photo-tile" src="{{img}}" mode="aspectFill"></image>
+        <image wx:if="{{im.isUrl(img)}}" class="photo-tile" src="{{img}}" mode="aspectFill"
+               catchtap="onPreviewImage" data-urls="{{item.images}}" data-cur="{{img}}"></image>
         <view wx:else class="photo-tile">{{img}}</view>
       </block>
     </view>