feat: 社保/公积金缴纳截止日改为按账户配置

- SocialAccount 模型增加 paymentDay 字段
- detectMonthlyTasks 社保/公积金改为按账户 paymentDay 生成提醒
- 账户表单增加缴纳截止日输入
- 设置页面移除社保/公积金缴纳日，保留发薪日和个税日

backend/prisma/schema.prisma

@@ -481,6 +481,7 @@ model SocialAccount {
   orgName       String?  // 缴费主体名称（子公司/分公司名称）
   orgCode       String?  // 缴费主体统一社会信用代码
   accountType   String?  // 公积金账户类型 BASIC=基本, SUPPLEMENTARY=补充
+  paymentDay    Int?     // 每月缴纳截止日（1-28），用于按账户生成缴纳提醒
   isDefault     Boolean  @default(false)
   status        String   @default("ACTIVE") // ACTIVE=正常, SUSPENDED=停用
   remark        String?

backend/src/routes/social.routes.ts

@@ -51,6 +51,7 @@ const accountSchema = z.object({
   orgName: z.string().optional(),
   orgCode: z.string().optional(),
   accountType: z.string().optional(),
+  paymentDay: z.number().int().min(1).max(28).optional(),
   isDefault: z.boolean().optional(),
   remark: z.string().optional(),
 })

backend/src/services/risk.service.ts

@@ -406,19 +406,16 @@ export async function detectMonthlyTasks(orgId: string) {
   const currentMonth = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}`
   const today = now.getDate()
 
-  const tasks = [
+  // 工资和个税仍用全局通知设置
+  const globalTasks = [
     { day: setting.payrollDay, title: `${currentMonth}月 发放工资`, desc: `每月${setting.payrollDay}日前完成工资发放`, url: '/money?tab=batch' },
-    { day: setting.socialInsDay, title: `${currentMonth}月 缴纳社保`, desc: `每月${setting.socialInsDay}日前完成社保缴纳`, url: '/social?tab=monthly' },
-    { day: setting.housingFundDay, title: `${currentMonth}月 缴纳公积金`, desc: `每月${setting.housingFundDay}日前完成公积金缴纳`, url: '/social?tab=monthly' },
     { 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; 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
+  for (const task of globalTasks) {
     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,
@@ -432,6 +429,27 @@ export async function detectMonthlyTasks(orgId: string) {
     }
   }
 
+  // 社保和公积金按账户 paymentDay 生成提醒
+  const accounts = await prisma.socialAccount.findMany({
+    where: { orgId, status: 'ACTIVE', paymentDay: { not: null } },
+  })
+  for (const acc of accounts) {
+    const day = acc.paymentDay!
+    if (today >= day) {
+      const deadline = new Date(now.getFullYear(), now.getMonth(), day)
+      const typeLabel = acc.type === 'SOCIAL' ? '社保' : '公积金'
+      risks.push({
+        employeeId: null,
+        type: 'MONTHLY',
+        level: today > day + 3 ? 'HIGH' : 'MEDIUM',
+        title: `${currentMonth}月 缴纳${typeLabel}（${acc.name}）`,
+        description: `账户「${acc.name}」每月${day}日前完成${typeLabel}缴纳`,
+        actionUrl: '/social?tab=monthly',
+        deadline,
+      })
+    }
+  }
+
   // 工资条生成提醒：当月有已归档批次时提醒生成工资条
   const archivedBatches = await prisma.payrollBatch.count({
     where: { orgId, month: currentMonth, status: 'ARCHIVED' },