fix: 日历风险截止事件按 employeeId:type 去重，避免重复提醒

backend/src/services/risk.service.ts

@@ -1167,7 +1167,7 @@ export async function getMonthlyCalendar(orgId: string, month: string) {
     }
   }
 
-  // 5. 风险截止日期
+  // 5. 风险截止日期（按 employeeId:type 去重，同一员工同一类型只保留最新一条）
   const riskDeadlines = await prisma.riskItem.findMany({
     where: {
       orgId,
@@ -1175,8 +1175,13 @@ export async function getMonthlyCalendar(orgId: string, month: string) {
       deadline: { gte: monthStart, lte: monthEnd },
     },
     include: { employee: true },
+    orderBy: { createdAt: 'desc' },
   })
+  const seenRiskKeys = new Set<string>()
   for (const r of riskDeadlines) {
+    const dedupKey = `${r.employeeId}:${r.type}`
+    if (r.employeeId && seenRiskKeys.has(dedupKey)) continue
+    if (r.employeeId) seenRiskKeys.add(dedupKey)
     events.push({
       date: r.deadline!.toISOString().slice(0, 10),
       type: 'RISK_DEADLINE',