fix(web): allow optional chat status in cancelInflight helper

Unblocks Docker web build after ChatMessage.status became optional.

web/src/lib/squadCompletionObservation.ts

@@ -33,7 +33,7 @@ export function isInflightChatStatus(status: string): boolean {
 type InflightCancelableMessage = {
   sessionId?: string;
   role: string;
-  status: string;
+  status?: string;
   livePhaseLabel?: string;
 };
 
@@ -50,6 +50,7 @@ export function cancelInflightAssistantMessages<T extends InflightCancelableMess
     if (
       message.sessionId === sessionId &&
       message.role === 'assistant' &&
+      message.status !== undefined &&
       isInflightChatStatus(message.status)
     ) {
       return {