Cross-workspace data disclosure via unchecked WebSocket binding

Incorrect authorization in AppFlowy Cloud 0.9.64 and earlier allows remote authenticated users to read collaborations across workspaces. The establish_ws_connection_v2 handler binds a session to a URL-supplied workspace without checking membership, while Manifest reads authorize only the bound workspace and fetch collaboration state by object identifier alone. Exploitation requires a valid account and a victim object identifier, but no victim interaction; successful requests disclose full document or database state without modifying it.