Feature request shift + enter for a new line in the chat

Hello,

First of all, thank you for providing this.
I would like to request the following feature:

I want to be able to press shift + enter, like in most chat program to format messages across multiple lines.
Right now, this combination just sends the message to the LLM.

Best regards
Lennart

Look for the chat input component, likely in a file like ChatInput.tsx or similar. Find the event handler for the keydown event and modify it to check for Shift+Enter to insert a newline, while keeping Enter alone to send the message. Test the change in the browser to ensure both actions work correctly.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.