Text input loses focus after user prompt

Small UI improvement: I have to take my hands off of the keyboard to re-click the focus on the text input bar in the following scenario.

1. Focus is on the text input.
2. Enter a message that will produce a user prompt ("Ask me the next question in this list") and hit enter to send the message
3. The session retains focus on the text input so you can choose an answer to the user prompt using the keyboard and press Enter to select.
4. When the user prompt decision is made and you switch back to "normal" (the turn ends?) the focus is no longer on the keyboard

Expected:
I should be able to keep my hands on the keyboard through user prompts and other prompts. If focus was on the text input during the user prompt, it should remain on the text input without having to click back in to continue.

At 0:04, I would assume that as soon as I press enter to select option A the focus would return:

https://github.com/user-attachments/assets/8dad1754-4f2a-4d85-9bf2-9acf28cc76b6

---
| Field | Value |
| --- | --- |
| App version | 1.1.13 |
| OS | macOS 26.6.2 |
| Theme | Rainglow Lavender |
| Path | /chat |
| Tenure | Week 4 |

在 macOS 上，按照所描述的用户提示流程，从文本输入和提示选择交互开始，在 /chat 路径中复现该问题。完成标准是：选择一个选项并返回正常对话后，焦点仍保持在文本输入框上，且不需要鼠标点击。

由索引模型根据 Issue 内容生成。