fix: 创建员工时从身份证解析性别和出生日期

- contract.service.ts createEmployee: gender 为空时从身份证第17位解析，birthDate 从第7-14位提取
- portal.routes.ts GET /profile: gender/birthDate 为空时从身份证 fallback 解析
- gender 统一使用中文 男/女（与数据库和其他服务一致）
- 前端 MyProfile.tsx 性别显示适配中文

backend/src/services/contract.service.ts

@@ -410,12 +410,13 @@ export async function createEmployee(orgId: string, userId: string, data: any) {
         monthlySalary: encrypt(data.monthlySalary),
         baseSalary: encrypt(String(baseSalaryNum)),
         performanceSalary: encrypt(String(performanceSalaryNum)),
-        gender: data.gender,
+        gender: data.gender || (data.idCardNumber ? extractGenderFromIdCard(data.idCardNumber) : null),
         femaleWorkerType: data.femaleWorkerType,
         phone: data.phone,
         passwordHash,
         idCardNumber: data.idCardNumber ? encrypt(data.idCardNumber) : null,
         idCardHash: data.idCardNumber ? sha256(data.idCardNumber) : null,
+        birthDate: data.idCardNumber ? extractBirthDateFromIdCard(data.idCardNumber) : null,
         isPregnant: data.isPregnant || false,
         isInMedicalPeriod: data.isInMedicalPeriod || false,
         isWorkInjured: data.isWorkInjured || false,