Lanefan
Victoria Rules
Yep.but somehow social interaction doesn't need to be mechanically structured? even though there's still the same divide between player and character as all the rest of the game, social interaction gets to work different simply just because it's easier to perform at the table?
Except substitute "can be performed at the table at all" for "easier to perform at the table".
The other option is to have binding social mechanics, but then (IMO valid) issues arise around player agency over their characters when those mechanics get turned against them. And no, having the mechanics only work in one direction is a complete non-starter: if a PC can do it to an NPC then for in-setting consistency the same is and must be possible in reverse.
So, the answer is no social mechanics.