Feature request: allow a message typed mid-turn to be queued for the next turn instead of injected immediately

Currently, when you type a message while Claude Code is actively working (running tools mid-turn), it gets injected into the current turn as soon as the active tool call finishes. This is useful for steering, but there's no way to opt a specific message out of that — you either let it interleave immediately, or press Esc to stop the whole turn and start fresh.

Requesting a way to send a message that queues and is only delivered to Claude once the current turn fully completes, while other messages sent in the same session keep the default immediate-injection behavior. E.g. a /queue <message> command, or a modifier key/prefix that marks a single message as "hold until turn end" without interrupting the running turn.

The only current workarounds (Esc to interrupt, or --input-format stream-json in non-interactive -p mode) either interrupt the whole turn or require abandoning the interactive session entirely — neither supports selective per-message deferral in interactive use.