修正測試腳本：更新覆蓋率報告輸出路徑

變更：
- run_integration_tests.bat:
  - 修改輸出路徑從 docs/validation/coverage/ 到專案根目錄 htmlcov/
  - 移除 XML 報告（改為終端輸出）
  - 配合清理後的專案結構

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>

run_integration_tests.bat

@@ -2,4 +2,4 @@
 chcp 65001
 set PYTHONIOENCODING=utf-8
 call conda activate timeline_designer
-pytest tests/integration/ --cov=backend --cov-report=html:docs/validation/coverage/htmlcov --cov-report=xml:docs/validation/coverage/coverage.xml -v
+pytest tests/integration/ --cov=backend --cov-report=html:htmlcov --cov-report=term -v