refactor: 重构数据库相关功能，移除旧的数据库模块，更新API路由以使用新的数据库接口，增强代码结构和可维护性

workflow_service/routes/workflow.py

@@ -5,7 +5,12 @@ from fastapi import APIRouter, Body, HTTPException, Path
 from fastapi.responses import JSONResponse
 
 from workflow_service import comfyui_client
-from workflow_service import database
+from workflow_service.database.api import (
+    save_workflow,
+    get_all_workflows,
+    delete_workflow,
+    get_workflow,
+)
 
 
 workflow_router = APIRouter(
@@ -25,7 +30,7 @@ async def publish_workflow_endpoint(data: dict = Body(...)):
             raise HTTPException(
                 status_code=400, detail="`name` and `workflow` fields are required."
             )
-        await database.save_workflow(name, json.dumps(wf_json))
+        await save_workflow(name, json.dumps(wf_json))
         print(f"Workflow '{name}' published.")
         return JSONResponse(
             content={"status": "success", "message": f"Workflow '{name}' published."},
@@ -43,7 +48,7 @@ async def get_all_workflows_endpoint():
     获取所有工作流
     """
     try:
-        return await database.get_all_workflows()
+        return await get_all_workflows()
     except Exception as e:
         raise HTTPException(status_code=500, detail=f"Failed to get workflows: {e}")
 
@@ -59,7 +64,7 @@ async def delete_workflow_endpoint(
     删除工作流
     """
     try:
-        success = await database.delete_workflow(workflow_name)
+        success = await delete_workflow(workflow_name)
         if success:
             return {"status": "deleted", "name": workflow_name}
         else:
@@ -75,7 +80,7 @@ async def get_one_workflow_endpoint(base_name: str, version: Optional[str] = Non
     """
     获取工作流规范
     """
-    workflow_data = await database.get_workflow(base_name, version)
+    workflow_data = await get_workflow(base_name, version)
 
     if not workflow_data:
         detail = (