Preserve message content when chat send fails (#605)

When users try to send a message while disconnected from the chat,
the message was being cleared even though it failed to send. This was
because handleSendMessage returned early without throwing an error,
so the .then() block in MessageInput executed and cleared the input.

Now handleSendMessage throws an error when not connected, which is
caught by MessageInput's error handler, preserving the user's message
in the input box so they don't lose their typed content.

https://claude.ai/code/session_012EqUZa3tCdhg3hHkBQkDdg

Co-authored-by: Claude <noreply@anthropic.com>

Author: jon-bell

components/realtime-chat.tsx

@@ -244,11 +244,7 @@ export const RealtimeChat = ({
   const handleSendMessage = useCallback(
     async (message: string) => {
       if (!isConnected) {
-        toaster.error({
-          title: "Not connected to chat",
-          description: "Please wait for the chat to connect before sending messages."
-        });
-        return;
+        throw new Error("Please wait for the chat to connect before sending messages.");
       }
       if (!message.trim() || !sendMessage || moderationStatus.isBanned) return;