feat(workflow): add Dify workflow import adapter and related APIs

api/app/schemas/app_schema.py

@@ -5,6 +5,8 @@ from enum import Enum, StrEnum
 
 from pydantic import BaseModel, Field, ConfigDict, field_serializer, field_validator
 
+from app.schemas.workflow_schema import WorkflowConfigCreate
+
 
 # ---------- Multimodal File Support ----------
 
@@ -196,6 +198,8 @@ class AppCreate(BaseModel):
     # only for type=multi_agent
     multi_agent_config: Optional[Dict[str, Any]] = None
 
+    workflow_config: Optional[WorkflowConfigCreate] = None
+
 
 class AppUpdate(BaseModel):
     name: Optional[str] = None