refactor: remove custom font-weight scss and update class usages

Delete the standalone font-weight.scss utility file, remove its import from the main scss index, and update all existing references to the custom font-{weight} classes to use either built-in semantic font utilities or inline functional font weight classes matching the project's utility-first styling pattern.

src/pages/ChatModule/AnswerComponent/index.vue

@@ -5,7 +5,7 @@
     <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]">
-        <text class="font-size-16 font-600 text-[#0B5C2D]"> {{ title }}</text>
+        <text class="font-size-16 font-[600] text-[#0B5C2D]"> {{ title }}</text>
       </view>
       <!-- 文字内容，根据数据模式限制预览行数 -->
       <view v-if="processedContent" class="answer-content font-size-12 font-color-600" :style="answerContentStyle">
@@ -13,11 +13,11 @@
       </view>
       <!-- 超过2行时显示...提示 -->
       <view v-if="!finish" class="flex flex-row flex-items-center mt-[8px]">
-        <text class="font-size-12 font-500 font-color-600">正在生成</text>
+        <text class="font-size-12 font-[500] font-color-600">正在生成</text>
         <ChatLoading />
       </view>
       <view v-if="isOverflow" class="flex flex-row flex-items-center flex-justify-between mt-[12px]">
-        <text class="font-size-12 font-800 text-[#cbd5e1] mr-[4px]">查看完整{{ tag }}</text>
+        <text class="font-size-12 font-bold text-[#cbd5e1] mr-[4px]">查看完整{{ tag }}</text>
         <uni-icons type="right" size="16" color="#CBD5E1"></uni-icons>
       </view>