feat: 全部列表页统一分页 + WorkProcess集成现有服务

- WorkProcess/Termination/Evidence/Contracts/Policies/Templates 添加 Pagination 组件
- 后端 getDrafts/getPolicies/enterprise-template 路由添加分页支持（可选参数，向后兼容）
- work-process.service CONFIRM case 修正：移除不存在的 probationEndDate 字段
- 新增 migration_add_three_tables.sql 增量迁移文件

backend/src/routes/termination.routes.ts

@@ -162,7 +162,9 @@ router.get('/drafts', authMiddleware, async (req: AuthRequest, res, next) => {
     const status = req.query.status as string | undefined
     const search = req.query.search as string | undefined
     const department = req.query.department as string | undefined
-    const result = await getDrafts(req.user!.orgId, status, search, department)
+    const page = parseInt(req.query.page as string) || 1
+    const pageSize = Math.min(parseInt(req.query.pageSize as string) || 20, 200)
+    const result = await getDrafts(req.user!.orgId, status, search, department, page, pageSize)
     res.json({ success: true, data: result })
   } catch (err) {
     next(err)