refactor(*): 代码质量 - 优化前后端实现并完善协议与画布验证

backend/internal/app/cloud_agent_layout.go

@@ -5,9 +5,9 @@ import (
 	"math"
 	"strings"
 
-	"infinite-canvas/backend/internal/canvas/layout"
-	"infinite-canvas/backend/internal/model"
-	"infinite-canvas/backend/internal/repository"
+	"yingce/backend/internal/canvas/layout"
+	"yingce/backend/internal/model"
+	"yingce/backend/internal/repository"
 )
 
 // 云端 Agent 的节点整理：模型只决定"整理哪些节点 / 怎么归类"，几何一律由服务端算。