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

packages/core/src/factory.ts

@@ -59,7 +59,7 @@ export function defaultRequestData(kind: RequestKind) {
     case "websocket":
       return {
         kind,
-        url: "wss://echo.websocket.events",
+        url: "wss://echo.websocket.org",
         headers: [],
         protocols: "",
       } satisfies WebsocketRequestData;
@@ -228,7 +228,7 @@ export function createSeedWorkspace(): WorkspaceData {
     ]),
     createFolder("实时协议", [
       createRequest("websocket", "WebSocket · echo", {
-        data: { url: "wss://echo.websocket.events" },
+        data: { url: "wss://echo.websocket.org" },
         description: "发送什么就回什么。",
       }),
       createRequest("sse", "SSE · 维基媒体变更流", {