"Secrets" count on stats post-it includes mods

The current behaviour of the stats screen is to sum together the number of achievements from mods and vanilla.

In my opinion, it makes more sense to only display the vanilla count, as it is having the 637 vanilla achievements that changes the save slot icon, and it's more convenient for the count to reflect progress towards Dead God. Additionally, toggling mods with achievements will change the number of modded secrets, making that total less useful.

An alternative is to separate the counts, ie render both the vanilla and modded totals separated by a plus, or on separate lines (which requires extending the post-it).
Or, this could be turned into a setting (vanilla count only / modded count only / summed totals), but it feels significantly too niche to be one.

The issue does not name an implementation file, test, or entry point. First locate the stats screen's post-it rendering and achievement-count calculation, then resolve whether the intended result is vanilla-only or separate totals; done means the displayed count matches the agreed behavior and no longer changes with enabled mod achievements.