Since the last update, I implemented a complete Flashcards module end-to-end. This included new database migrations and models for decks, cards, and card reviews, plus the associations needed to connect users, decks, and review history.

I also finished the full MVC flow for flashcards:

• Deck management (create, list, view, update, delete).
• Card management inside decks (create, update, delete).
• Review flow with due cards and answer submission.
• Review progress endpoint for tracking performance over time.

On the logic side, I added mastery score calculation and a spaced-review style due-date strategy based on correct and wrong attempts. I also fixed integration issues from this cycle, including model naming, async promise handling, and boolean behavior in requests.