feat(test-case): 测试耗时自动计算（逻辑同开发任务）

- TestCase 新增 startedAt / completedAt 字段
- 流转到"执行中"时记录 startedAt
- 流转到"通过/失败/阻塞"时记录 completedAt
- 回退到执行中时清除 completedAt
- 测试耗时 = startedAt → completedAt 工作日 × 8h
- 列表行显示耗时，详情抽屉显示开始/完成/耗时

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/components/test-case/TestCaseDetailDrawer.tsx

@@ -8,6 +8,7 @@ import { useTestCaseStore } from '@/stores/useTestCaseStore';
 import { useBugStore } from '@/stores/useBugStore';
 import { useRequirementStore } from '@/stores/useRequirementStore';
 import { TC_ALLOWED_TRANSITIONS, TEST_CASE_STATUS_LABEL } from '@/lib/test-case';
+import { calcActualHoursByDates } from '@/lib/dev-task';
 import { BUG_SEVERITY_LABEL, BUG_SEVERITY_COLOR } from '@/lib/bug';
 import type { TestCaseStatus } from '@/lib/test-case';
 
@@ -126,6 +127,9 @@ export function TestCaseDetailDrawer({ testCaseId, onClose, onCreateBug }: Props
               <div><span className="text-[var(--ink-muted)]">负责人：</span><span className="text-[var(--ink)] font-medium">{tc.assigneeId || '-'}</span></div>
               <div><span className="text-[var(--ink-muted)]">创建人：</span><span className="text-[var(--ink)]">{tc.createdBy}</span></div>
               <div><span className="text-[var(--ink-muted)]">创建日期：</span><span className="text-[var(--ink)]">{tc.createdAt.slice(0, 10)}</span></div>
+              {tc.startedAt && <div><span className="text-[var(--ink-muted)]">开始执行：</span><span className="text-[var(--ink)]">{tc.startedAt}</span></div>}
+              {tc.completedAt && <div><span className="text-[var(--ink-muted)]">执行完成：</span><span className="text-[var(--ink)]">{tc.completedAt}</span></div>}
+              {tc.startedAt && <div><span className="text-[var(--ink-muted)]">测试耗时：</span><span className="text-[var(--ink)] font-medium">{calcActualHoursByDates(tc.startedAt, tc.completedAt)}h</span></div>}
             </div>
           </div>
 

apps/web/components/test-case/TestCaseRow.tsx

@@ -1,8 +1,8 @@
 'use client';
 
 import { TestCaseStatusBadge } from './TestCaseStatusBadge';
+import { calcActualHoursByDates } from '@/lib/dev-task';
 import type { TestCase } from '@/lib/test-case';
-import type { Bug } from '@/lib/bug';
 
 interface Props {
   testCase: TestCase;
@@ -24,6 +24,9 @@ export function TestCaseRow({ testCase, bugCount, onClick }: Props) {
       <span className="text-[11px] font-mono text-[var(--ink-muted)] w-14 shrink-0">{testCase.caseNo}</span>
       <span className="text-[13px] text-[var(--ink)] flex-1 truncate">{testCase.title}</span>
       <TestCaseStatusBadge status={testCase.status} />
+      {testCase.startedAt && (
+        <span className="text-[11px] text-[var(--ink-muted)] tabular-nums w-10 text-right">{calcActualHoursByDates(testCase.startedAt, testCase.completedAt)}h</span>
+      )}
       {bugCount > 0 && (
         <span className="text-[10px] text-red-500 bg-red-50 px-1.5 py-0.5 rounded">{bugCount} Bug</span>
       )}