feat(health): 随访模板系统 — follow_up_template + template_field 全栈

新增随访模板和模板字段两张表及完整 CRUD：
- 迁移 083: follow_up_template + follow_up_template_field
- Entity: 模板(名称/类型/适用范围/状态) + 字段(标签/键名/类型/选项/校验)
- DTO: 创建时内嵌字段列表、更新支持全量替换字段
- Service: 随访类型+字段类型校验、级联软删除
- Handler: 5 端点 + RBAC 权限
- 路由: /api/v1/health/follow-up-templates

crates/erp-health/src/service/mod.rs

@@ -16,6 +16,7 @@ pub mod dialysis_prescription_service;
 pub mod dialysis_service;
 pub mod doctor_service;
 pub mod follow_up_service;
+pub mod follow_up_template_service;
 pub mod health_data_service;
 pub mod masking;
 pub mod patient_service;