The change about migration looks good.
Can you create a pull request, though this is second time saying? It's difficult for me to track changes from issue comments. Surely learning Git is not easy. But adding entry script and continuing to modify it is easy even if you are not familiar with Git because Gitea allows you to edit files in your browser.
Gitea itself doesn't have documentation for that. But GitHub's ones are so helpful:
Can you consider it? Thanks.
No, it's not possible.
I also think it would be a nice feature what you're saying.
Sorry, there's no listing neither examples. But documentation is here: https://docs.joinplu.me/guide/creating-themes/
Copying default theme from static directory is a good start point.
It might be good to move database-related code from request handlers to models.