refactor: replace custom line-height classes with tailwind leading utils

Remove the deprecated src/static/scss/line-height.scss custom utility file, and update all component template instances of line-height-* classes to use the equivalent tailwind leading-[xxpx] utilities. This standardizes line height styling across the codebase by using native tailwind classes instead of custom SCSS helpers.

src/pages/ChatMain/ChatQuickAccess/index.vue

@@ -5,7 +5,7 @@
         @click="sendReply(item)">
         <view class="flex items-center justify-center">
           <image v-if="item.icon" class="icon" :src="item.icon" />
-          <text class="font-size-14 theme-color-500 line-height-20">
+          <text class="font-size-14 theme-color-500 leading-[20px]">
             {{ item.title }}
           </text>
         </view>

src/pages/ChatMain/ChatTopWelcome/index.vue

@@ -6,7 +6,7 @@ v
         <SpriteAnimator :src="spriteStyle.ipLargeImage" :frameWidth="spriteStyle.frameWidth"
           :frameHeight="spriteStyle.frameHeight" :totalFrames="spriteStyle.totalFrames" :columns="spriteStyle.columns"
           :displayWidth="spriteStyle.displayWidth" :fps="16" />
-        <view class="welcome-text font-size-14 font-500 font-family-misans-vf color-171717 line-height-24">
+        <view class="welcome-text font-size-14 font-500 font-family-misans-vf color-171717 leading-[24px]">
           {{ welcomeContent }}
         </view>
       </view>

src/pages/ChatMain/NoticeMessage/detail.vue

@@ -18,7 +18,7 @@
             <text class="color-171717 font-size-12 font-weight-600 ml-8">发布时间：{{ publishTime }}</text>
           </view>
 
-          <view class="mt-20 pt-[16px] color-666 font-size-14 line-height-20 border-top">{{ noticeContent }}</view>
+          <view class="mt-20 pt-[16px] color-666 font-size-14 leading-[20px] border-top">{{ noticeContent }}</view>
         </view>
       </view>
     </scroll-view>