fix: 退休检测排除劳务协议等非劳动合同类型

detectRetirementRisks 和日历退休日期查询均增加 contracts 过滤，
只检测 FIXED/UNFIXED 正式劳动合同员工，与 updateEmployeesRetirementDays 一致

backend/src/services/risk.service.ts

@@ -488,7 +488,7 @@ 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 } },
+    where: { orgId, status: 'ACTIVE', birthDate: { not: null }, contracts: { some: { contractType: { in: ['FIXED', 'UNFIXED'] } } } },
     select: { id: true, name: true, gender: true, birthDate: true, femaleWorkerType: true },
   })
 
@@ -1204,12 +1204,13 @@ export async function getMonthlyCalendar(orgId: string, month: string) {
     })
   }
 
-  // 6. 退休日期
+  // 6. 退休日期（仅正式劳动合同员工）
   const retiringEmployees = await prisma.employee.findMany({
     where: {
       orgId,
       status: 'ACTIVE',
       retirementDaysLeft: { gte: 0, lte: 365 },
+      contracts: { some: { contractType: { in: ['FIXED', 'UNFIXED'] } } },
     },
   })
   for (const emp of retiringEmployees) {