feat(assets): 使用 file-saver 库优化文件下载功能

- 引入 file-saver 库替代手动创建下载链接的方式
- 在 asset-transfer.ts 中使用 saveAs 替代 URL.createObjectURL 和手动点击链接
- 在 canvas-export.ts 中使用 saveAs 替代原有的文件下载逻辑
- 更新 package.json 添加 file-saver 依赖
- 更新 bun.lock 文件同步依赖变更

web/src/app/(user)/canvas/[id]/canvas-client-page.tsx

@@ -4,6 +4,7 @@ import { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } fr
 import type { ChangeEvent as ReactChangeEvent, DragEvent as ReactDragEvent, MouseEvent as ReactMouseEvent, PointerEvent as ReactPointerEvent } from "react";
 import { useParams, useRouter } from "next/navigation";
 import { Home, ImageIcon, Images, List, Menu, MessageSquare, Plus, Redo2, Settings2, Trash2, Undo2, Upload, Video } from "lucide-react";
+import { saveAs } from "file-saver";
 
 import { requestEdit, requestGeneration, requestImageQuestion } from "@/services/api/image";
 import { requestVideoGeneration } from "@/services/api/video";
@@ -1317,10 +1318,7 @@ function InfiniteCanvasPage() {
 
     const downloadNodeImage = useCallback((node: CanvasNodeData) => {
         if ((node.type !== CanvasNodeType.Image && node.type !== CanvasNodeType.Video) || !node.metadata?.content) return;
-        const link = document.createElement("a");
-        link.href = node.metadata.content;
-        link.download = `canvas-${node.type}-${node.id}.${node.type === CanvasNodeType.Video ? "mp4" : imageExtension(node.metadata.content)}`;
-        link.click();
+        saveAs(node.metadata.content, `canvas-${node.type}-${node.id}.${node.type === CanvasNodeType.Video ? "mp4" : imageExtension(node.metadata.content)}`);
     }, []);
 
     const saveNodeAsset = useCallback(