Setup and implement API to enforce limits (Paywall backend)

[geropl]

On StartWorkspace, check if a limit has been hit, and notify the client.

[AlexTugarev]

This issue reads like a repetition of 1.) from #11403
@geropl, what should be done in here exactly?

[geropl]

@AlexTugarev Kind of, but more about the wrapping and communicating the signal to frontend. 👍

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.