feat(web,hub): cancel queued messages (#568)

hub/src/sync/syncEngine.ts

@@ -9,7 +9,7 @@
 
 import type { CodexCollaborationMode, DecryptedMessage, PermissionMode, Session, SyncEvent } from '@hapi/protocol/types'
 import type { Server } from 'socket.io'
-import type { Store } from '../store'
+import type { Store, CancelQueuedMessageResult } from '../store'
 import type { RpcRegistry } from '../socket/rpcRegistry'
 import type { SSEManager } from '../sse/sseManager'
 import { EventPublisher, type SyncEventListener } from './eventPublisher'
@@ -312,6 +312,13 @@ export class SyncEngine {
         this.sessionCache.markMessageQueued(sessionId)
     }
 
+    async cancelQueuedMessage(
+        sessionId: string,
+        messageId: string
+    ): Promise<CancelQueuedMessageResult> {
+        return this.messageService.cancelQueuedMessage(sessionId, messageId)
+    }
+
     async approvePermission(
         sessionId: string,
         requestId: string,