Persist the beatmap offset of the previous play across sessions

[Tunnelbliick]

Hello,

ive been Playing exclusively on lazer for quite a while now and personally love the automatic offset calibration.

With the recent update that persists the calibration value even when leaving and re-entering the same map (as long as no other map is played in between), I found myself wondering why osu! doesn't store this value locally for each beatmap until it is either forcibly cleared, applied, or overwritten by a new play.

The reason for this suggestion is that I've often played a beatmap that needed a local offset, after switching to a different map and coming back later—even in a different session—the previously recorded average hit error was gone. (as designed)

I believe that implementing a feature to locally store this value would further enhance the system, provided it can be done in a lightweight manner. I assume this is not currently the case.

Even if only the numerical offset value (e.g., 1.06ms early) from a previous session is stored—without the full graph—this would still be a significant improvement. It would allow players to resume play with their previously determined offset and could likely be implemented within the local osu! database with minimal resource usage.