fix: 月度任务截止日使用配置的实际日期，不再用 today+N天 硬编码

detectMonthlyTasks 生成风险时设置 deadline 为当月配置的截止日
runRiskDetection 创建记录时优先使用风险自带的 deadline

backend/src/services/risk.service.ts

@@ -449,11 +449,13 @@ export async function detectMonthlyTasks(orgId: string) {
     { day: setting.taxDay, title: `${currentMonth}月 申报个税`, desc: `每月${setting.taxDay}日前完成个税申报`, url: '/money?tab=batch' },
   ]
 
-  const risks: { employeeId: null; type: RiskType; level: RiskLevel; title: string; description: string; actionUrl: string }[] = []
+  const risks: { employeeId: null; type: RiskType; level: RiskLevel; title: string; description: string; actionUrl: string; deadline?: Date }[] = []
 
   for (const task of tasks) {
     // 当月已过截止日或正好到截止日时生成提醒
     if (today >= task.day) {
+      // deadline 为当月截止日
+      const deadline = new Date(now.getFullYear(), now.getMonth(), task.day)
       risks.push({
         employeeId: null,
         type: 'MONTHLY',
@@ -461,6 +463,7 @@ export async function detectMonthlyTasks(orgId: string) {
         title: task.title,
         description: task.desc,
         actionUrl: task.url,
+        deadline,
       })
     }
   }
@@ -664,7 +667,7 @@ export async function runRiskDetection(orgId: string) {
         actionUrl: r.actionUrl,
         estimatedLoss: cost.estimatedLoss,
         lossRange: cost.lossRange,
-        deadline: cost.deadline,
+        deadline: (r as any).deadline || cost.deadline,
       }
     })
     await prisma.riskItem.createMany({ data: createData })