✨ feat(vscode): 工单移交的会话包改走阿里云 OSS、换 xz 压缩，两边进度一步步显示

- 会话包传到 OSS 的 spx-handoff/<owner>/<repo>/issue-<N>-<时间>.tar.xz，上传时对象设成私有；不再挂 Gitea 工单附件
- 新命令「配置移交存储」：endpoint、bucket 存扩展设置，AccessKey 存密钥存储；没配时移交 / 接管直接提示，什么都不改
- 共享 state 字段 handoffAttachmentId 改名 handoffBundleKey（含 spx CLI 与 schema）
- 打包换成 xz 1 级（tar -cJf），去掉 100MB 上限检查和先试压一遍的重复压缩
- 发送方提示打包 / 上传了多少 MB；接管方同一条提示依次显示下载、解包、建 worktree、装会话，完成前不消失
- 会话交接（单会话）仍走 Gitea 附件，Gitea 附件白名单没有 .xz，单独保留 gzip 打包

vscode/package.json

@@ -33,6 +33,7 @@
     "onView:superpowers.kanban",
     "onCommand:superpowers.openKanban",
     "onCommand:superpowers.setGiteaToken",
+    "onCommand:superpowers.configureHandoffStore",
     "onUri",
     "onView:superpowers.codeReader.files",
     "onCustomEditor:superpowers.codeReader.preview",
@@ -107,6 +108,11 @@
         "title": "Set Gitea Token",
         "category": "Superpowers"
       },
+      {
+        "command": "superpowers.configureHandoffStore",
+        "title": "配置移交存储",
+        "category": "Superpowers"
+      },
       {
         "command": "superpowers.codeReader.pickReviewIssue",
         "title": "选工单",
@@ -515,6 +521,7 @@
   },
   "dependencies": {
     "@vscode/tree-sitter-wasm": "^0.3.1",
+    "ali-oss": "^6.23.0",
     "diff": "^9.0.0",
     "handlebars": "^4.7.9",
     "ignore": "^7.0.10",
@@ -523,6 +530,7 @@
   },
   "devDependencies": {
     "@antfu/eslint-config": "^6.7.3",
+    "@types/ali-oss": "^6.23.3",
     "@types/diff": "^8.0.0",
     "@types/node": "^25.0.3",
     "@types/vscode": "^1.97.0",