Should we add a projection abstraction?

[dgoerdes]

In the example app we highlight the importance of the revision field for projections.

export const User = z.object({
    _id: z.string().length(24),
    id: z.string(),

    // The revision is an important bit of
    // information. We set the latest event id
    // from the EventSourcingDB related to this user
    // here.
    // This is used to resume the projection if the
    // application is restarted. We do not want to
    // apply all events again but pick up where we left off.
    //
    // See also getUserProjectionLowerBound() in users.projection.ts
    // for additional details on this.
    revision: z.string(),

    email: z.string(),
    firstName: z.string(),
    lastName: z.string(),
    invitedAt: z.string(),
    acceptedAt: z.string().nullable(),
});

Would it be good to add some abstraction for projections to Nimbus?
How should this look like, e.g. a type or interface that could simply be extended?