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

frontend/src/pages/Policies.tsx

@@ -6,6 +6,7 @@ import api from '../lib/api'
 import Card from '../components/ui/Card'
 import Button from '../components/ui/Button'
 import EmptyState from '../components/ui/EmptyState'
+import Pagination from '../components/ui/Pagination'
 
 const STEP_LABELS: Record<string, string> = {
   DRAFTING: '起草',
@@ -23,14 +24,18 @@ export default function Policies() {
   const queryClient = useQueryClient()
   const [showCreate, setShowCreate] = useState(false)
   const [selectedPolicy, setSelectedPolicy] = useState<any>(null)
+  const [page, setPage] = useState(1)
+  const [pageSize, setPageSize] = useState(20)
 
-  const { data: list, isLoading } = useQuery<any>({
-    queryKey: ['policies'],
+  const { data: listData, isLoading } = useQuery<any>({
+    queryKey: ['policies', page, pageSize],
     queryFn: async () => {
-      const res = await api.get('/policies') as any
+      const res = await api.get('/policies', { params: { page, pageSize } }) as any
       return res.data
     },
   })
+  const list = listData?.items || []
+  const total = listData?.total || 0
 
   const advanceMutation = useMutation({
     mutationFn: ({ id, step, note }: { id: string; step: number; note?: string }) => api.post(`/policies/${id}/advance-step`, { step, note }),
@@ -114,6 +119,13 @@ export default function Policies() {
           ))}
         </div>
       )}
+      <Pagination
+        page={page}
+        pageSize={pageSize}
+        total={total}
+        onPageChange={setPage}
+        onPageSizeChange={(s) => { setPageSize(s); setPage(1) }}
+      />
 
       {/* 详情弹窗 */}
       {selectedPolicy && (