Live-Update on Stacks and Cards

When multiple users work together in Nextcloud Deck, changes to stacks and cards (such as moving, editing, or creating) are not updated in real-time for other users. This requires manual page refreshes to see the latest state, which can interrupt the workflow.

Proposed feature:
Implement live updates (e.g., using WebSockets or a similar mechanism) so that all changes to stacks and cards are instantly visible to all participants without needing to reload the page. This would greatly improve the collaborative experience, similar to how other real-time collaboration tools work.

Benefits:

Smoother collaboration for teams.

Reduced chance of conflicts or overwriting changes.

More modern and responsive user experience.

Example use case:
Two users are organizing a project board simultaneously. One user moves a card to a different stack, and the change is instantly reflected on the other user’s screen without requiring a page reload.

No files, tests, or entry points are named. Start by tracing how stack and card creation, editing, and moving currently reach other users, then determine where live update delivery and client handling would belong. Done means those changes appear for other participants without a page refresh and the collaborative flows are covered by tests.