refactor: 删除 PRE_ONBOARD 显式状态，统一按入职日期判定预入职

预入职不再需要显式设置 PRE_ONBOARD 状态，统一按入职日期自动
判定：入职日期在未来 = 预入职（不进入薪资），入职日期 <= 今天
= 正式在职。

删除内容：
- schema: EmployeeStatus 枚举移除 PRE_ONBOARD
- roster.routes.ts: 移除 PRE_ONBOARD 筛选和 /activate API
- payroll2.routes.ts: 移除 NOT PRE_ONBOARD 排除条件
- modals.tsx: 移除入职状态选择器

保留：按 hireDate > 今天 自动判定预入职的逻辑

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

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

backend/src/routes/payroll2.routes.ts

@@ -340,8 +340,6 @@ router.post('/batches', async (req: AuthRequest, res: Response, next: NextFuncti
               { status: 'ACTIVE' },
               { status: 'RESIGNED', updatedAt: { gte: monthStart, lte: monthEnd } },
             ],
-            // 预入职员工不进入薪资批次
-            NOT: { status: 'PRE_ONBOARD' },
           },
           include: { contracts: { orderBy: { createdAt: 'desc' }, take: 1 } },
         })

backend/src/routes/roster.routes.ts

@@ -101,17 +101,12 @@ router.get('/', authMiddleware, async (req: AuthRequest, res, next) => {
     if (status === 'RESIGNED') {
       whereBase.status = 'RESIGNED'
     } else if (status === 'PRE_HIRE' || status === 'PRE_ONBOARD') {
-      // 预入职：PRE_ONBOARD 状态，或 ACTIVE 状态但入职日期在未来
-      whereBase.OR = [
-        { status: 'PRE_ONBOARD' },
-        { status: 'ACTIVE', hireDate: { gt: todayEnd } },
-      ]
+      // 预入职：ACTIVE 状态但入职日期在未来（按入职日期自动判定）
+      whereBase.status = 'ACTIVE'
+      whereBase.hireDate = { gt: todayEnd }
     } else if (status === 'ACTIVE') {
       whereBase.status = 'ACTIVE'
       whereBase.hireDate = { lte: todayEnd }
-    } else if (!status) {
-      // 无状态过滤时，排除 PRE_ONBOARD（默认只看在职和离职）
-      whereBase.NOT = { status: 'PRE_ONBOARD' }
     }
 
     // unsigned 合同状态可以在 DB 层过滤
@@ -1606,20 +1601,4 @@ router.get('/contract-types', authMiddleware, (_req: AuthRequest, res) => {
   res.json({ success: true, data: types })
 })
 
-// 预入职转正式（PRE_ONBOARD → ACTIVE）
-router.post('/:id/activate', authMiddleware, async (req: AuthRequest, res, next) => {
-  try {
-    const emp = await prisma.employee.findFirst({ where: { id: req.params.id, orgId: req.user!.orgId! } })
-    if (!emp) return res.status(404).json({ success: false, error: { code: 'NOT_FOUND', message: '员工不存在' } })
-    if (emp.status !== 'PRE_ONBOARD') {
-      return res.status(400).json({ success: false, error: { code: 'BAD_REQUEST', message: '该员工不是预入职状态' } })
-    }
-    const updated = await prisma.employee.update({
-      where: { id: emp.id },
-      data: { status: 'ACTIVE' },
-    })
-    res.json({ success: true, data: { id: updated.id, status: updated.status } })
-  } catch (err) { next(err) }
-})
-
 export default router