[Feature request] Customizable popups for RetroAcheivements?

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

Would it be possible to implement a way of adding our own customized popups for RetroAchievements please?

Expected behavior

• For example, the ability to have options for: Slide-in from left or right like PS4 trophies, Fade-in like PS5 trophies or Fade-in and Expand like Xbox achievements?

• Ability to change the look and layout of the RetroAchievements popup eg. fonts, styles, popup box etc

Actual behavior

There is only one default look and animation for RetroAchievements at this time that cannot be changed.

Steps to reproduce the bug

When a RetroAchievement is obtained

Bisect Results

[Try to bisect and tell us when this started happening]

Version/Commit

RetroArch: 1.16.0

• RetroArch: [version/commit]

Environment information

• OS: Any
• Compiler: [In case you are running local builds]

Start by examining the RetroAchievements popup shown when an achievement is obtained; the issue provides no file, test, or entry point to follow. Define the supported animation and appearance options, then verify the result across the requested popup styles and layouts.