fix(eio-client): restore default transport resolution

Keep transport names as the ordered list used for connection attempts, while
storing transport constructors in a separate lookup map. This restores default
transport resolution, keeps constructor-based transports for backward
compatibility, and avoids mutating user-provided transport arrays during
fallback/reconnect attempts.

New syntax:

```js
import { Socket, XHR, WebSocket } from "engine.io-client";

const socket = new Socket({
  transportImplementations: [XHR, WebSocket]
});
```

Related:

- #5197
- #5327
- #5330

See also: socketio/engine.io-client@f4d898e

Author: darrachequesne

packages/engine.io-client/lib/index.ts

@@ -5,9 +5,9 @@ export {
   HandshakeData,
   SocketOptions,
   SocketReservedEvents,
-  SocketWithoutUpgrade,
-  SocketWithUpgrade,
   WriteOptions,
+  TransportCtor,
+  TransportName,
 } from "./socket.js";
 export const protocol = Socket.protocol;
 export {