A replay system for Minecraft matches: record everything that happened, store
it, and let a player watch it back afterwards.
### The interesting part isn't Minecraft
Recording a match is the easy half. The hard half is that a busy network
produces thousands of replays and every one of them has to be cheap to keep and
fast to load. So replays get compressed with zstd, the blobs go to S3-compatible
object storage through MinIO, and the metadata — who played, which kit, when,
how long — lives in MongoDB so it can be queried without touching the blobs.
Playback runs on slime worlds, which load and unload far faster than regular
world files, and the whole packet layer goes through PacketEvents.
### Stack
Java 17, Gradle with shadow, MongoDB, MinIO, zstd-jni, PacketEvents. Built
against GhostSpigot, split into an api module and the plugin itself.