优化: 添加员工弹窗-身份证号必填+性别自动识别

1. 身份证号必填（18位），后端加密存储
2. 性别由身份证号第17位自动计算（奇数=男，偶数=女），无需手动选择
3. 移除添加员工时的孕期/医疗期/工伤复选框（这些状态后续在员工档案中维护）

backend/src/services/contract.service.ts

@@ -164,6 +164,7 @@ export async function createEmployee(orgId: string, userId: string, data: any) {
       monthlySalary: encrypt(data.monthlySalary),
       gender: data.gender,
       phone: data.phone,
+      idCardNumber: data.idCardNumber ? encrypt(data.idCardNumber) : null,
       isPregnant: data.isPregnant || false,
       isInMedicalPeriod: data.isInMedicalPeriod || false,
       isWorkInjured: data.isWorkInjured || false,

frontend/src/pages/Roster.tsx

@@ -931,13 +931,22 @@ function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
   })()
   const [form, setForm] = useState({
     name: '', department: '', hireDate: todayStr, monthlySalary: '',
-    gender: '男' as '男' | '女', phone: '',
-    isPregnant: false, isInMedicalPeriod: false, isWorkInjured: false,
+    idCardNumber: '', gender: '男' as '男' | '女', phone: '',
     contractType: 'FIXED' as 'FIXED' | 'UNFIXED' | 'UNSIGNED',
     signDate: '', startDate: todayStr, endDate: defaultEndDate,
     contractYears: 3, probationMonths: 0, probationSalary: 0,
   })
 
+  // 根据身份证号自动计算性别（第17位：奇数=男，偶数=女）
+  const handleIdCardChange = (idCard: string) => {
+    let gender = form.gender
+    if (idCard.length >= 17) {
+      const digit = parseInt(idCard[16])
+      if (!isNaN(digit)) gender = digit % 2 === 1 ? '男' : '女'
+    }
+    setForm({ ...form, idCardNumber: idCard, gender })
+  }
+
   // 计算合同月数
   const contractMonths = (() => {
     if (form.contractType !== 'FIXED' || !form.startDate) return 0
@@ -1017,8 +1026,8 @@ function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
       name: form.name, department: form.department,
       hireDate: new Date(form.hireDate).toISOString(),
       monthlySalary: form.monthlySalary, gender: form.gender,
+      idCardNumber: form.idCardNumber || undefined,
       phone: form.phone || undefined,
-      isPregnant: form.isPregnant, isInMedicalPeriod: form.isInMedicalPeriod, isWorkInjured: form.isWorkInjured,
     }
     if (form.contractType !== 'UNSIGNED' && form.startDate) {
       data.contract = {
@@ -1033,6 +1042,7 @@ function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
   }
 
   const canSubmit = form.name && form.department && form.hireDate && form.monthlySalary
+    && form.idCardNumber.length >= 18
     && (form.contractType === 'UNSIGNED' || form.startDate)
     && !probationError && !probationSalaryError
 
@@ -1048,19 +1058,17 @@ function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
           <div><Label>姓名 *</Label><Input value={form.name} onChange={(e) => setForm({ ...form, name: e.target.value })} placeholder="员工姓名" /></div>
           <div><Label>部门 *</Label><Input value={form.department} onChange={(e) => setForm({ ...form, department: e.target.value })} placeholder="如：技术部" /></div>
         </div>
+        <div className="grid grid-cols-2 gap-3">
+          <div><Label>身份证号 *</Label><Input value={form.idCardNumber} onChange={(e) => handleIdCardChange(e.target.value)} placeholder="18位身份证号" maxLength={18} /></div>
+          <div><Label>性别</Label><div className="text-xs text-gray-600 py-1.5">{form.idCardNumber.length >= 17 ? form.gender : '由身份证号自动识别'}</div></div>
+        </div>
         <div className="grid grid-cols-2 gap-3">
           <div><Label>入职日期 *</Label><Input type="date" value={form.hireDate} onChange={(e) => setForm({ ...form, hireDate: e.target.value })} /></div>
           <div><Label>月工资 *</Label><Input type="number" value={form.monthlySalary} onChange={(e) => setForm({ ...form, monthlySalary: e.target.value })} placeholder="元" /></div>
         </div>
         <div className="grid grid-cols-2 gap-3">
-          <div><Label>性别</Label><Select value={form.gender} onChange={(e) => setForm({ ...form, gender: e.target.value as '男' | '女' })}><option value="男">男</option><option value="女">女</option></Select></div>
           <div><Label>手机号</Label><Input value={form.phone} onChange={(e) => setForm({ ...form, phone: e.target.value })} placeholder="选填" maxLength={11} /></div>
         </div>
-        <div className="flex gap-4">
-          <label className="flex items-center gap-1.5 text-xs"><input type="checkbox" checked={form.isPregnant} onChange={(e) => setForm({ ...form, isPregnant: e.target.checked })} />孕期/哺乳期</label>
-          <label className="flex items-center gap-1.5 text-xs"><input type="checkbox" checked={form.isInMedicalPeriod} onChange={(e) => setForm({ ...form, isInMedicalPeriod: e.target.checked })} />医疗期</label>
-          <label className="flex items-center gap-1.5 text-xs"><input type="checkbox" checked={form.isWorkInjured} onChange={(e) => setForm({ ...form, isWorkInjured: e.target.checked })} />工伤</label>
-        </div>
         <div className="border-t pt-3">
           <Label>合同类型</Label>
           <Select value={form.contractType} onChange={(e) => setForm({ ...form, contractType: e.target.value as any, endDate: e.target.value === 'UNFIXED' ? '' : form.endDate })}>