feat(canvas): 实现画布项目导出为ZIP压缩包功能

- 新增 canvas-export 工具模块，支持将画布项目打包为 ZIP 文件
- 修改导出功能，将原来的 JSON 格式改为 ZIP 压缩包，包含 projects.json 和相关媒体文件
- 添加对 fflate 库的依赖用于 ZIP 文件处理
- 更新画布库页面，支持多选项目批量导出
- 修改导入功能以支持读取新版 ZIP 格式的画布项目
- 新增 zip 处理工具库，封装压缩和解压操作
- 扩展文件存储服务，添加获取和设置 Blob 对象的方法
- 更新 AGENTS.md 文档，添加标准库使用原则

web/bun.lock

@@ -17,6 +17,7 @@
         "clsx": "^2.1.1",
         "copy-to-clipboard": "^4.0.2",
         "dayjs": "^1.11.20",
+        "fflate": "^0.8.3",
         "localforage": "^1.10.0",
         "lucide-react": "^1.16.0",
         "motion": "^12.38.0",
@@ -802,6 +803,8 @@
 
     "fetch-blob": ["fetch-blob@3.2.0", "https://registry.npmmirror.com/fetch-blob/-/fetch-blob-3.2.0.tgz", { "dependencies": { "node-domexception": "^1.0.0", "web-streams-polyfill": "^3.0.3" } }, "sha512-7yAQpD2UMJzLi1Dqv7qFYnPbaPx7ZfFK6PiIxQ4PfkGPyNyl2Ugx+a/umUonmKqjhM4DnfbMvdX6otXq83soQQ=="],
 
+    "fflate": ["fflate@0.8.3", "", {}, "sha512-tbZNuJrLwGUp3zshBtdy4W+ORxZuIh8a5ilyIEQDC5rY1f3U20JMry0Ll3WBzU58EZKsEuJFXhb5gwv8CsPvgA=="],
+
     "figures": ["figures@6.1.0", "https://registry.npmmirror.com/figures/-/figures-6.1.0.tgz", { "dependencies": { "is-unicode-supported": "^2.0.0" } }, "sha512-d+l3qxjSesT4V7v2fh+QnmFnUWv9lSpjarhShNTgBOfA0ttejbQUAlHLitbjkoRiDulW0OPoQPYIGhIC8ohejg=="],
 
     "fill-range": ["fill-range@7.1.1", "https://registry.npmmirror.com/fill-range/-/fill-range-7.1.1.tgz", { "dependencies": { "to-regex-range": "^5.0.1" } }, "sha512-YsGpe3WHLK8ZYi4tWDg2Jy3ebRz2rXowDxnld4bkQB00cc/1Zw9AWnC0i9ztDJitivtQvaI9KaLyKrc+hBW0yg=="],