feat: add onWsClose callback to LoroWebsocketClient options (#2)

Author: Leeeon233

packages/loro-websocket/src/client/index.ts

@@ -63,7 +63,7 @@ export class LoroWebsocketClient {
   }> = [];
 
   constructor(
-    private ops: { url: string; pingIntervalMs?: number; disablePing?: boolean }
+    private ops: { url: string; pingIntervalMs?: number; disablePing?: boolean, onWsClose?: () => void }
   ) {
     this.connectedPromise = new Promise<void>((resolve, reject) => {
       this.ws = new WebSocket(this.ops.url);
@@ -102,6 +102,7 @@ export class LoroWebsocketClient {
     // Clear timers and pending waiters on close
     this.ws.addEventListener('close', () => {
       this.clearPingTimer();
+      this.ops.onWsClose?.();
       this.rejectAllPingWaiters(new Error("WebSocket closed"));
     });
   }