fix: 发薪日缺省5号+通知设置去掉重复发薪日字段

backend/prisma/schema.prisma

@@ -130,7 +130,7 @@ model Organization {
   city         String?
   contactName  String?
   contactPhone String?
-  payrollDays         Json     @default("[]")  // 每月发薪日期，如 [5, 20] 表示每月5号和20号
+  payrollDays         Json     @default("[5]")  // 每月发薪日期，如 [5, 20] 表示每月5号和20号
   payrollReminderDays Int      @default(3)     // 发薪提前提醒天数
   retirementReminderEnabled Boolean @default(false) // 退休提醒开关
   esignPolicyEnabled  Boolean @default(false) // 规章制度电子签

frontend/src/pages/Settings.tsx

@@ -94,7 +94,7 @@ function OrgSettings({ orgData, onSave, saving }: { orgData: any; onSave: (data:
     name: '',
     contactName: '',
     contactPhone: '',
-    payrollDays: [] as number[],
+    payrollDays: [5] as number[],
     payrollReminderDays: 3,
     retirementReminderEnabled: false,
     esignPolicyEnabled: false,
@@ -108,7 +108,7 @@ function OrgSettings({ orgData, onSave, saving }: { orgData: any; onSave: (data:
         name: orgData.name || '',
         contactName: orgData.contactName || '',
         contactPhone: orgData.contactPhone || '',
-        payrollDays: Array.isArray(orgData.payrollDays) ? orgData.payrollDays : [],
+        payrollDays: Array.isArray(orgData.payrollDays) && orgData.payrollDays.length > 0 ? orgData.payrollDays : [5],
         payrollReminderDays: orgData.payrollReminderDays ?? 3,
         retirementReminderEnabled: orgData.retirementReminderEnabled || false,
         esignPolicyEnabled: orgData.esignPolicyEnabled || false,
@@ -881,11 +881,7 @@ function NotificationSettings() {
           <div className="border-t pt-3 space-y-3">
             <div className="text-xs font-medium">月度事务提醒</div>
             <div className="text-xs text-gray-500">设置每月截止日，到期后自动生成待办提醒</div>
-            <div className="grid grid-cols-2 gap-3">
-              <div>
-                <Label>发薪日（每月几号）</Label>
-                <Input type="number" min={1} max={28} value={form.payrollDay ?? 10} onChange={(e) => setForm({ ...form, payrollDay: Number(e.target.value) })} />
-              </div>
+            <div className="grid grid-cols-3 gap-3">
               <div>
                 <Label>社保缴纳日</Label>
                 <Input type="number" min={1} max={28} value={form.socialInsDay ?? 15} onChange={(e) => setForm({ ...form, socialInsDay: Number(e.target.value) })} />