feat(canvas): 生图设置 - 支持透明背景输出 (#29) (#31)

Co-authored-by: linxi <linxi@enjoysoftware.cn>

web/src/types/canvas.ts

@@ -146,6 +146,7 @@ export type CanvasNodeMetadata = {
     model?: string;
     size?: string;
     quality?: string;
+    transparentBackground?: string;
     count?: number;
     seconds?: string;
     vquality?: string;