Implementing 'Optimistic UI' Updates with Pinia and Vue Reactivity

Optimistic UI involves updating the local state immediately before the server confirms the action, with a rollback mechanism if the request fails.

To provide a 'latency-free' experience, the store should apply changes instantly. Architecturally, the action must save a 'snapshot' of the state before the change. If the API returns an error, the store catches the exception and reverts the state to the snapshot. This is critical for high-frequency interactions like 'Liking' a post or dragging an item in a Kanban board.