feat: UI scale slider?

some apps have massive text, while on my phone for 1/2 players the life text is only half the width or so.

the UI scale slider should be between the current value and max width

No files or tests are named. Start by locating the existing UI scale slider and the life-text layout, then compare the current slider value with the maximum width on the phone player view. Done means the slider provides a usable value between those bounds so the life text can occupy more of the available width.

Written by the indexing model from the issue text.