优化: 无障碍第二批(icon-only aria-label + 容器键盘化 20 处)

- TopBar 10 处 icon-only 按钮补 aria-label(复用同 :title 表达式,含三态 title)
- ConversationSidebar: 4 icon-only aria-label + 2 分组标题键盘化(role/tabindex/aria-expanded/keydown)
- MessageList 2 icon-only; KnowledgeDetail 3 章节折叠键盘化; dashboard 两列表项键盘化
- FileExplorer 面包屑/模块下拉项键盘化; ConflictResolver 冲突文件折叠键盘化
- 约定: 遮罩/点外关闭类(@click.self)非键盘缺口,跳过;零新增 i18n 键
- 验收: bunx vue-tsc --noEmit EXIT 0;看板 P3-2 更新(两批共 23 处)

src/components/dashboard/IdeasPanel.vue

@@ -19,7 +19,7 @@
       </div>
     </div>
     <div class="idea-rows">
-      <div v-for="idea in displayIdeas" :key="idea.id" class="idea-row clickable" @click="goDetail(idea.id)" :title="t('dashboard.goIdeaDetail')">
+      <div v-for="idea in displayIdeas" :key="idea.id" class="idea-row clickable" role="button" tabindex="0" @click="goDetail(idea.id)" @keydown.enter.prevent="goDetail(idea.id)" @keydown.space.prevent="goDetail(idea.id)" :title="t('dashboard.goIdeaDetail')">
         <div class="idea-score-ring" :class="'ring-' + idea.tier">
           <span class="idea-score-num">{{ idea.score }}</span>
         </div>