ZK | ⁓ repeat wrong items four trials later

part of the ‣ StudySmarter #spaced-repetition algo
alternative to repeating wrong items after n seconds
~ you can schedule items by time or by trial
doing this now in #project-karten , kind of (new cards are first freely memorized, than integrated into normal SR flow, but blocked for four ⁓ think in trials or so, because otherwise would be weird and boring)