feat: 20260815 系统优化 - 全部31项问题修复(P0×6+P1×14+P2×9+P3×2)

P0紧急修复(6项):
- 草稿保存完整恢复所有字段(含socialAvgWage)
- 补偿金批次从compensationBreakdown读取
- 违法解除风险确认UI
- 合同结束日期前后校验(前后端双保险)

P1高优先级(14项):
- 离职日期联动社保/公积金截止月(15号规则)
- 合规检查+工作交接改为软阻断(生成待办)
- 补偿月数(N/N+1/2N/自定义)+计算基数(近12月/合同/自定义)
- 解聘并入花名册操作栏(类型选择跳转向导)
- 合同续签开始日期自动推导(原合同结束日+1天)
- 年龄合规筛查(童工阻断/未成年工/退休警告)
- 编辑入职日期后状态联动(待入职↔在职)
- 转正移植到花名册操作栏+薪资回写
- 男职工无法选择三期

P2体验优化(9项):
- "劳动合同"调整为"用工关系"
- 费用结算新增剩余年假折算(300%日工资)
- 身份证号全域改为"证件号码"(前后端18个文件)
- 手机号查重
- 开具证明+合同续签移植到花名册操作栏
- 批量转正+批量开具证明
- 去掉用工办理模块

P3规划(2项):
- 组织架构+审批流(Department/Position/ApprovalFlow/ApprovalInstance)
- 客服工作台(Ticket/ChatSession+SUPPORT角色)

新增模型: Department/Position/ApprovalFlow/ApprovalInstance/Ticket/TicketMessage/ChatSession/ChatMessage
新增字段: Employee.departmentId/supervisorId
新增角色: SUPPORT

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

backend/src/services/contract.service.ts

@@ -31,7 +31,7 @@ async function clampHousingFundBase(orgId: string, base: number, city?: string):
   return base
 }
 
-function prevMonth(month: string): string {
+export function prevMonth(month: string): string {
   const [y, m] = month.split('-').map(Number)
   const d = new Date(y, m - 2, 1)
   return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}`
@@ -209,14 +209,14 @@ export async function getEmployeeDetail(orgId: string, id: string) {
 }
 
 export async function createEmployee(orgId: string, userId: string, data: any) {
-  // 身份证号查重
+  // 证件号码查重
   if (data.idCardNumber) {
     const existing = await prisma.employee.findFirst({
       where: { orgId, idCardHash: sha256(data.idCardNumber) },
       select: { id: true, name: true, department: true, status: true },
     })
     if (existing) {
-      throw { code: 'DUPLICATE_ID_CARD', message: `身份证号已存在：${existing.name}（${existing.department}，${existing.status === 'ACTIVE' ? '在职' : '离职'}），请确认是否重复录入` }
+      throw { code: 'DUPLICATE_ID_CARD', message: `证件号码已存在：${existing.name}（${existing.department}，${existing.status === 'ACTIVE' ? '在职' : '离职'}），请确认是否重复录入` }
     }
   }
 
@@ -591,6 +591,7 @@ export async function updateEmployee(orgId: string, id: string, data: any) {
   if (data.city !== undefined) updateData.city = data.city
   if (data.education !== undefined) updateData.education = data.education
   if (data.position !== undefined) updateData.position = data.position
+  if (data.status !== undefined) updateData.status = data.status
 
   // 参保城市变更：关闭旧城市在保记录，创建新城市记录
   if (data.city !== undefined && data.city !== employee.city) {