chore: WebSocket 演示地址切换为 wss://echo.websocket.org（含存量数据迁移）

packages/ui/src/workspaceStore.ts

@@ -148,6 +148,15 @@ function sanitizeCollections(collections: Collection[]): Collection[] {
   const fix = (nodes: CollectionNode[]): CollectionNode[] =>
     nodes.map((n) => {
       if (n.type === "folder") return { ...n, children: fix(n.children) };
+      // 一次性迁移：旧演示地址更新为新的公共 echo 服务
+      if (
+        n.type === "request" &&
+        n.kind === "websocket" &&
+        n.data &&
+        (n.data as { url?: string }).url === "wss://echo.websocket.events"
+      ) {
+        (n.data as { url: string }).url = "wss://echo.websocket.org";
+      }
       if (n.type === "request" && (!n.data || !n.kind)) {
         const kind = (n.kind ?? "http") as RequestKind;
         return {