style(web): 移除顶栏 AI 快捷操作区并优化差旅领导意见事件样式

- TopBar 移除 AI 模式下的公司切换/AI 模式切换快捷操作块及 showAiModeUtilityActions 计算属性，清理 top-bar.css 对应样式
- TravelRequestDetailView 领导意见事件重构为状态/意见/审批人结构化布局，travel-request-detail-view.css 补充对应样式
- 同步更新 topbar-ai-mode-switch、ai-sidebar-rail-mode、travel-request-detail-leader-approval 测试

web/src/components/layout/TopBar.vue

@@ -367,23 +367,6 @@
         </div>
       </template>
 
-      <div v-if="showAiModeUtilityActions" class="topbar-utility-actions" aria-label="AI模式快捷操作">
-        <button class="company-switcher" type="button" aria-label="切换公司">
-          <span>{{ displayCompanyName }}</span>
-          <i class="mdi mdi-chevron-down"></i>
-        </button>
-        <button
-          type="button"
-          class="topbar-ai-mode-toggle"
-          :class="{ active: isTopbarAiMode }"
-          :aria-pressed="isTopbarAiMode"
-          :aria-label="topbarWorkbenchModeTitle"
-          :title="topbarWorkbenchModeTitle"
-          @click="toggleTopbarWorkbenchMode"
-        >
-          <span class="topbar-ai-mode-toggle__glyph">AI</span>
-        </button>
-      </div>
     </div>
   </header>
 </template>
@@ -488,7 +471,6 @@ const displayCompanyName = computed(() => String(props.companyName || '远光软
 const isTopbarAiMode = computed(() => props.workbenchMode === 'ai')
 const topbarWorkbenchModeTitle = computed(() => (isTopbarAiMode.value ? 'AI 模式，点击切换传统模式' : '传统模式，点击切换 AI 模式'))
 const isWorkbenchAiHome = computed(() => isWorkbench.value && isTopbarAiMode.value)
-const showAiModeUtilityActions = computed(() => isTopbarAiMode.value && !isWorkbench.value)
 const MAX_NOTIFICATION_ITEMS = 30
 const {
   markDocumentInboxRowRead,