Allow custom scheduling js to modify card.desired_retention

[abdo]

Relevant:

Customisable queue and repetition algorithm

Feature request - how difficult would it be to incorporate custom metadata into Anki’s scheduling algorithms? E.g. cards with the ‘high priority’ tag automatically have shorter repetition intervals, and appear earlier in the review queue than cards with the ‘medium priority’ tag. I understand that the repetition intervals can be manually adjusted, and that cards can be sorted into filtered decks with custom intervals. However, this is less intuitive and more fragile than a simple per-card metad…