/btw side-question gets queued instead of running in parallel during active streaming

Describe the bug

Typed /btw [question] while Claude was actively streaming a response. Instead of getting an ephemeral side answer in a dismissible overlay (as advertised in hints), the message was queued and only processed after Claude finished the main task.

Steps to reproduce

1. Give Claude a multi-step task that takes several seconds to complete
2. While Claude is actively streaming its response, type /btw [any question]
3. Observe: message is queued, not handled in parallel

Expected behavior

Side question answered immediately in a dismissible overlay without interrupting or entering conversation history.

Actual behavior

Message enters the queue. Claude finishes the main task first, then processes the /btw message as a normal turn.

Environment

• OS: WSL2 (Linux 6.6.87.2-microsoft-standard-WSL2)
• Claude Code: latest
• Model: claude-sonnet-4-6