Optimize user experience

[fengwk]

1. PreviewWindow used "force" for tbl_deep_extend, so the parameters passed from outside would always be invalid. I modified it. Additionally, I attempted to support passing UI attribute configurations through the configuration file.
2. If in insert mode, the chat would still be in insert mode upon exit. Therefore, I switched back to normal mode upon exit.
3. Code edits did not have a binding for "close," so I added the ability to bind "close."

These are all small modifications, but they have greatly improved my experience. I hope they can be merged.

[jackMort]

Please also fix stylua errors to pass checks, thanks!

[fengwk]

I have corrected comments language and stylua errors ~