新增多证书模板管理流程

backend/app/schemas/certificate.py

@@ -13,6 +13,7 @@ class CertificateCreate(BaseModel):
     course_start_date: date
     course_end_date: date
     issue_date: date
+    template_code: str | None = Field(default=None, min_length=1, max_length=32)
     remark: str | None = None
 
     @field_validator("project_code")
@@ -44,6 +45,7 @@ class CertificateOut(BaseModel):
     course_end_date: date | None
     issue_date: date
     issuer_name: str
+    template_code: str
     status: str
     pdf_status: str
     created_at: datetime