TaskServer is not configured” banner does not disappear

### Description

When the app is opened and TaskServer is not configured, a banner appears at the bottom saying:

“TaskServer is not configured”

This banner does not disappear automatically and remains fixed on the screen indefinitely.
Expected behavior is that it should auto-hide after some time (like a snackbar/toast).

### Steps to reproduce

Steps to Reproduce

1. Open the app
2. Tap on refresh icon
3.Do not configure TaskServer
4.Observe the bottom banner

### What was the expected result?

The banner should disappear automatically after a few seconds
OR be dismissible by swipe/tap (if intended as persistent notification)

### Put here any screenshots or videos (optional)


### How can we contact you (optional)

_No response_

### Would you like to work on this issue?

None

### By submitting this issue, I have confirmed that:

- [x] I have starred the repo ⭐ and watched 👀 it on GitHub and followed the contribution guidelines.

首先在 Flutter 应用中复现该问题：打开应用，在未配置 TaskServer 的情况下点击刷新图标，并跟踪底部横幅的显示位置。完成标准是“TaskServer is not configured”通知在几秒后自动消失，或支持预期的关闭交互。

由索引模型根据 Issue 内容生成。