Supporting our growing number of free users

The post describes architectural changes to the free tier to support a rapidly growing number of daily signups. These changes include expanding cloud capacity, implementing a waitlist, archiving inactive indexes after 7 days (or 1 day for ephemeral indexes), and reviewing the free plan's architecture for long-term scalability. The new architecture runs in a `gcp-starter` region, enables instant sign-ups, allows free indexes to persist indefinitely, and reduces provisioning time to seconds. Features like namespaces, collections, and delete by metadata are removed from free indexes.