feat: enhance flow-approval UI with Ant Design components

- Implement FlowNodeHistory Timeline component with status icons and tags
- Refactor ApprovalLayout body with Ant Design Layout + Card + collapsible Sider
- Enhance ApprovalLayout header with title and improved button styling
- Add layout constants (ApprovalLayoutHeight, ApprovalSidebarWidth, etc.)
- Add approval design file (approval.pen)
- Add git-push command and CLAUDE.md documentation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: xlorne

designs/approval.pen

@@ -0,0 +1,3 @@
+# git push command
+
+根据当前调整内容，并创建git的提交指令，并添加对应的提交信息，然后执行git push命令将本地的提交推送到远程仓库。