feat(loro-websocket): add sendExternalUpdates method to LoroWebsocketClient

[lodyai]

Summary

Add a new public method sendExternalUpdates() to LoroWebsocketClient that allows users to send additional updates to a specified room that are not from the local peer's document.

Changes

• Added sendExternalUpdates(crdt, roomId, updates) method to LoroWebsocketClient
• The method validates that the room is active and WebSocket is open before sending
• Uses existing sendUpdateOrFragments() for proper fragmentation handling of large payloads

Use Case

This is useful for forwarding updates received from other sources or peers to a room, enabling scenarios where updates need to be relayed without originating from the local document.

API

sendExternalUpdates(
  crdt: CrdtType,
  roomId: string,
  updates: Uint8Array[]
): void

• crdt: The CRDT type of the room
• roomId: The room ID to send updates to
• updates: Array of update payloads to send
• Throws Error if not connected or room is not active