fix: prevent message disappearing when task ends during queueing

- Add null check in queueMessage handler to catch edge case where task ends between send click and message processing
- Send queueMessageFailed message to webview to restore user input
- Handle queueMessageFailed in ChatView to restore text and images
- Prevents user frustration from losing typed messages

src/core/webview/webviewMessageHandler.ts

@@ -3036,7 +3036,18 @@ export const webviewMessageHandler = async (
 		 */
 
 		case "queueMessage": {
-			provider.getCurrentTask()?.messageQueueService.addMessage(message.text ?? "", message.images)
+			const currentTask = provider.getCurrentTask()
+			if (!currentTask) {
+				// Task ended between when the user clicked send and when the message was processed
+				provider.log("Cannot queue message: No active task")
+				await provider.postMessageToWebview({
+					type: "queueMessageFailed",
+					text: message.text,
+					images: message.images,
+				})
+				break
+			}
+			currentTask.messageQueueService.addMessage(message.text ?? "", message.images)
 			break
 		}
 		case "removeQueuedMessage": {

src/shared/ExtensionMessage.ts

@@ -133,6 +133,7 @@ export interface ExtensionMessage {
 		| "browserSessionUpdate"
 		| "browserSessionNavigate"
 		| "claudeCodeRateLimits"
+		| "queueMessageFailed"
 	text?: string
 	payload?: any // Add a generic payload for now, can refine later
 	// Checkpoint warning message

webview-ui/src/components/chat/ChatView.tsx

@@ -820,6 +820,13 @@ const ChatViewComponent: React.ForwardRefRenderFunction<ChatViewRef, ChatViewPro
 						)
 					}
 					break
+				case "queueMessageFailed":
+					// Restore the message that failed to queue
+					if (message.text || (message.images && message.images.length > 0)) {
+						setInputValue(message.text || "")
+						setSelectedImages(message.images || [])
+					}
+					break
 				case "invoke":
 					switch (message.invoke!) {
 						case "newChat":