wtf is universe?

Universe is a tool that continuously copies your SpacetimeDB data to a second machine, so you always have an up-to-date backup or replica. It works like Litestream does for SQLite: instead of running a full backup job on a schedule, it watches your database files and streams every new change over the network in real time. To use it, you run a receiver process on your backup server and a sender process on your database server. The sender watches the SpacetimeDB data directory for any file changes and immediately transmits the new bytes to the receiver, which writes them into a matching folder structure. If you are setting up a brand-new replica, an optional flag tells the sender to copy everything first before switching to live-watching mode. The system handles network interruptions gracefully. The receiver keeps track of exactly how many bytes it has received from each file and periodically sends that information back to the sender. If the connection drops and reconnects, the sender simply resumes from where the receiver left off, so no data is duplicated or missed. Each chunk of data is also verified with a checksum to make sure nothing was corrupted in transit. This would be useful for teams running SpacetimeDB who need a standby replica in another data center, want a continuously updated copy for disaster recovery, or are preparing to migrate to new hardware without downtime. It is a straightforward, single-purpose tool: it replicates the raw data directory and nothing else. The README does not go into detail on monitoring, alerting, or encryption, so you would need to handle those concerns separately.