P0: submitRecord() 路径修正 POST /follow-up-records → POST /follow-up-tasks/{id}/records
+ 请求体从 {task_id, content:{text}} 改为 {result, patient_condition, executed_date}
P1: ConsultationSession.subject/last_message 改为可选(后端暂不返回)
P1: Appointment.department 改为可选(后端未 JOIN 医生表)
P1: FollowUpRecord 结构对齐后端扁平字段(executed_date/result/medical_advice 等)
P2: Article 增加 status 可选字段