/ask responses should not prompt for follow-up interaction

### Describe the feature or problem you'd like to solve

/ask should not prompt for replies because the user cannot interact in a multiturn way in this side session

### Proposed solution

Description:

/ask is documented as a single-turn side question that doesn't add to conversation history. However, the model's responses in /ask sessions often propose next steps, ask follow-up questions, and prompt the user to reply — even though there's no way to interact further. The
only option is pressing Esc, which discards the entire context.

Current behavior:

- User runs /ask with a question
- Model responds with an answer, then says something like "Would you like me to dig deeper into X?" or "Here are some options — which would you prefer?"
- User has no way to respond — can only press Esc and lose the context

Expected behavior:

- Model responses in /ask should be self-contained — give the full answer without expecting follow-up
- If there are natural next steps, frame them as actions the user can take back in the main session (e.g., "To explore this further, try asking in your main session: ..."). Provide something you can copy paste from this side conversation into your main or new session to take the next steps.
- Never ask questions or prompt for replies in /ask mode

Impact: Creates a confusing dead-end experience. Users feel like they're missing functionality or hitting a bug, when it's actually the model not adapting its response style to the single-turn constraint.

### Example prompts or workflows

_No response_

### Additional context

_No response_

Start at the /ask entry point in the CLI and trace how its single-turn context is sent to the model; the issue identifies no file or test. Done means /ask responses are self-contained, never ask for a reply, and provide copyable prompts or actions for continuing in the main session.

由索引模型根据 Issue 内容生成。