fix: 退休检测改为按最新合同类型判断，排除劳务协议员工

detectRetirementRisks、updateEmployeesRetirementDays、日历退休日期查询
均改为 include 最新合同并在代码中判断 contractType，而非用 some 查询
（some 会匹配到历史 FIXED 合同导致劳务人员仍被检测）

backend/src/services/risk.service.ts

@@ -488,13 +488,16 @@ export async function detectMonthlyTasks(orgId: string) {
  */
 export async function detectRetirementRisks(orgId: string) {
   const employees = await prisma.employee.findMany({
-    where: { orgId, status: 'ACTIVE', birthDate: { not: null }, contracts: { some: { contractType: { in: ['FIXED', 'UNFIXED'] } } } },
-    select: { id: true, name: true, gender: true, birthDate: true, femaleWorkerType: true },
+    where: { orgId, status: 'ACTIVE', birthDate: { not: null } },
+    include: { contracts: { orderBy: { createdAt: 'desc' }, take: 1 } },
   })
 
   const risks: { employeeId: string; type: RiskType; level: RiskLevel; title: string; description: string; actionUrl: string }[] = []
 
   for (const emp of employees) {
+    // 只对最新合同为正式劳动合同的员工进行退休检测
+    const latestContractType = emp.contracts[0]?.contractType
+    if (!latestContractType || !['FIXED', 'UNFIXED'].includes(latestContractType)) continue
     if (!emp.birthDate) continue
     const gender = emp.gender || '男'
     const fwt = emp.femaleWorkerType
@@ -1204,16 +1207,19 @@ export async function getMonthlyCalendar(orgId: string, month: string) {
     })
   }
 
-  // 6. 退休日期（仅正式劳动合同员工）
+  // 6. 退休日期（仅最新合同为正式劳动合同的员工）
   const retiringEmployees = await prisma.employee.findMany({
     where: {
       orgId,
       status: 'ACTIVE',
       retirementDaysLeft: { gte: 0, lte: 365 },
-      contracts: { some: { contractType: { in: ['FIXED', 'UNFIXED'] } } },
     },
+    include: { contracts: { orderBy: { createdAt: 'desc' }, take: 1 } },
   })
   for (const emp of retiringEmployees) {
+    // 只对最新合同为正式劳动合同的员工显示退休日期
+    const latestContractType = emp.contracts[0]?.contractType
+    if (!latestContractType || !['FIXED', 'UNFIXED'].includes(latestContractType)) continue
     if (emp.retirementDaysLeft !== null) {
       const retireDate = new Date()
       retireDate.setDate(retireDate.getDate() + emp.retirementDaysLeft)