Additional information from Google employee https://x.com/_mohansolo/status/2025766889205739899 :

"We’ve been seeing a massive increase in malicious usage of the Anitgravity backend that has tremendously degraded the quality of service for our users. We needed to find a path to quickly shut off access to these users that are not using the product as intended. We understand that a subset of these users were not aware that this was against our ToS and will get a path for them to come back on but we have limited capacity and want to be fair to our actual users."