Credits were previously awarded on any first attempt regardless of
correctness or timing. The award now requires the first-ever attempt
to be correct (record.Attempt.IsCorrect) and submitted before the
adaptive per-question timer expired (new MetTimeLimit request field,
computed client-side from the same elapsed/target comparison that
already drives the visible countdown bar). The coin-flight animation
in question_player.gd now only plays when both conditions are met
(BlockSessionService.submit_core_attempt's existing "mastered" flag
plus met_time_limit), so the effect never promises a coin that isn't
actually earned.
Co-Authored-By: Claude Sonnet 5 <[email protected]>