refactor: replace legacy flex utility classes and remove flex.scss

Replace all instances of prefixed flex utility classes (like flex-items-center, flex-justify-between, flex-full, flex-shrink-0) with their standard un-prefixed counterparts (items-center, justify-between, flex-1, shrink-0) across the codebase. Remove the deprecated src/static/scss/flex.scss partial file as it is no longer needed after these updates.

src/pages/ChatMain/NoticeMessage/detail.vue

@@ -1,19 +1,19 @@
 <template>
   <view class="flex flex-col bg-liner h-screen overflow-hidden">
     <!-- ✅ 顶部固定导航 -->
-    <view class="flex-shrink-0">
+    <view class="shrink-0">
       <TopNavBar :title="detailTitle" background="transparent" />
     </view>
 
     <!-- ✅ 滚动区域 -->
-    <scroll-view class="flex-full overflow-hidden" scroll-y>
+    <scroll-view class="flex-1 overflow-hidden" scroll-y>
       <view class="pb-[24px] overflow-hidden">
         <image v-if="coverImage" class="w-full h-auto block" :src="coverImage" mode="widthFix" />
 
         <view class="pt-[16px] px-[12px] pb-[24px] border-box">
           <view class="text-[#171717] text-[16px] font-weight-600">{{ detailTitle }}</view>
 
-          <view v-if="publishTime" class="notice-time-tag flex flex-row flex-items-center mt-[16px]">
+          <view v-if="publishTime" class="notice-time-tag flex flex-row items-center mt-[16px]">
             <uni-icons type="clock" size="18" color="#5A6780" />
             <text class="text-[#171717] text-[12px] font-weight-600 ml-[8px]">发布时间：{{ publishTime }}</text>
           </view>