refactor: migrate to tailwind arbitrary width classes

remove the unused src/static/scss/width.scss file and its import from index.scss, replace all existing custom width utility class usages with the equivalent Tailwind arbitrary width syntax

src/pages/ChatModule/AnswerComponent/index.vue

@@ -1,7 +1,7 @@
 <template>
   <view v-if="shouldRenderCard" class="w-full bg-white border-ff overflow-hidden rounded-[20px] flex flex-col">
     <!-- 占位撑开 -->
-    <view class="w-vw"></view>
+    <view class="w-screen"></view>
     <view class="flex flex-col px-[16px] pt-[16px] pb-[12px] border-box" @click="lookDetailAction">
       <view v-if="tag" class="long-answer-tag" :style="longAnswerTagStyle">{{ tag }}</view>
       <view v-if="title" class="flex flex-row flex-items-start flex-justify-start mb-[4px]">