Add aspect-ratio lock and remove maximum size limit for mini player #3239

Currently, the mini player (picture-in-picture) has a fixed default size and also enforces a maximum window size. I would like to request the following improvements:

1. Aspect-ratio lock during resizing – When manually resizing the mini player, it should maintain the video’s original aspect ratio, similar to the behavior in the official client.
2. Removal of the maximum size limit – The mini player should be allowed to scale freely without an upper size restriction.

These changes would make the mini player more flexible and consistent with the official client’s user experience.