[BUG] macOS desktop app: messages typed during an active turn are sent immediately instead of being queued

Summary

In the Claude Desktop app (Code tab), typing a message and pressing Enter while the assistant turn is still in flight does not queue the message. The message is submitted immediately instead of waiting for the current turn to finish.

Environment

• Claude Desktop 1.52386.6 (CFBundleShortVersionString / CFBundleVersion both 1.52386.6)
• macOS 15.6 (Darwin 25.6.0), Apple Silicon
• Claude Code session running inside the desktop app (Code tab), model Opus 5

Steps to reproduce

1. Open a session in the Code tab.
2. Send a prompt that takes a while (e.g. one that runs several tool calls).
3. While the assistant is visibly still working (streaming text / running tools), type a follow-up message and press Enter.

Expected

The follow-up is held as a queued message and delivered when the current turn completes (the documented queueing behavior).

Actual

The message is sent right away rather than being queued — no queued-message indicator appears.

Notes

• Reproduced by the user across multiple attempts, including while the turn was clearly active.
• Nothing queue-related appears in ~/Library/Logs/Claude/main.log or main-window.log; the only queue matches are unrelated (flushEventQueue on quit, change_directory queued, and enqueue=Nms in [CCD start-timing] lines). This looks like renderer-side behavior that is not logged, so there is no diagnostic output to attach.
• Searched open issues for "queued messages" / "message queue"; the closest ones (#87656, #93659, #77451, #93276) describe different symptoms (fold-mid-turn setting, Esc delivery, loss on session switch, iPadOS stuck turn), not "queueing never engages on macOS desktop".