-- Additive: completion threshold + per-day status for multi-day assignments.
-- Non-destructive: existing rows keep requiresReport / draftData / entries unchanged.

ALTER TABLE `assignment_definitions`
  ADD COLUMN `minValidDays` INTEGER NULL;

ALTER TABLE `assignment_daily_entries`
  ADD COLUMN `dayStatus` ENUM('done', 'skipped', 'difficult') NOT NULL DEFAULT 'done';