### What problem does this PR solve?

Fix: In the dark night theme, the message input box is not displayed
correctly. #6950

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?

Improves the chat interface by adding a multiline chat area that grows
when multiple lines exists.

Some images:

* Empty:
<img width="1334" alt="image"
src="https://github.com/user-attachments/assets/e8a68b46-def9-45af-b5b1-db0f0b67e6d8"
/>

* With multiple lines and documents:
<img width="1070" alt="image"
src="https://github.com/user-attachments/assets/ff976c5c-08fa-492f-9fc0-17512c95f9f2"
/>


### Type of change
- [X] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?
- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>
Co-authored-by: Jin Hai <haijin.chn@gmail.com>

### What problem does this PR solve?

feat: Delete the files uploaded in the external dialog box #1880

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?
feat: Add MessageInput to the external chat page #1880

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?

feat: Add FileIcon #1880

### Type of change


- [x] New Feature (non-breaking change which adds functionality)