[Suggestion] Add per-ruleset (Standard, Mania, etc.) skin and offset settings

[coo1red]

Currently, players have to manually change their skin and audio offset whenever they switch between game rulesets (e.g., from Standard to Mania).

It would be a huge QoL improvement if we could:

Assign specific skins to each ruleset so they switch automatically.

Set different audio offsets for each ruleset, as the timing feel between clicking circles and hitting keys in Mania can differ.

This would make the transition between different game modes much smoother for multi-mode players.

[bluebear94]

If this is added, it would be nice to be able to set your skin separately for different key counts in mania. I want to try out some custom skins for 4K, but for 7K, all the skins I’ve seen other than Argon I find ill-suited.