优化: i18n硬编码清扫(8文件20+处中文字符串替为i18n)

- ToolCard: 已等待 → aiTool.waitTime

- ErrorBoundary: 堆栈详情 → error.stackDetails

- TopBar: 10处硬编码(tooltip+section标签+单位) → aiChat.* keys

- FileExplorer: 4处工程操作title → fileExplorer.*

- Tasks: 快捷菜单4处 → tasks.*

- EnrichmentPanel: 取消关联 → aiChat.enrichmentDismiss

- PlanProgress: 复用已有 aiChat.conflictsPending

- WorkflowDagDisplay: 删除中文fallback(已有i18n key)

- vue-tsc + vite build 通过

src/components/workflow/WorkflowDagDisplay.vue

@@ -46,14 +46,14 @@
             @keydown.enter="saveCondition(i)"
             @keydown.escape="cancelEdit"
             @blur="saveCondition(i)"
-            :placeholder="$t('taskDetail.workflowCondPlaceholder') || '输入条件表达式'"
+            :placeholder="$t('taskDetail.workflowCondPlaceholder')"
           />
           <span
             v-else
             class="wf-dag-cond-label"
             :class="{ 'wf-dag-cond-label--uncond': !edge.condition, 'wf-dag-cond-label--editable': true }"
             @click="startEdit(i, edge)"
-          >{{ edge.condition || ($t('taskDetail.workflowUnconditional') || '无条件') }}</span>
+          >{{ edge.condition || $t('taskDetail.workflowUnconditional') }}</span>
         </div>
       </div>
     </details>