- ShardGate: shard entity ticking into per-shard CAS gates so slow shards
skip a tick instead of blocking the whole barrier
- EntityTickParallel: collect entities by stable id into shards, submit via
ShardGate, count missed shards
- FineGrainScheduler: add submitShard path with gate release and barrier
counting
- SectionStorageMixin: replace global exclusive synchronized map with
ConcurrentLong2ObjectMap to remove the POI read lock bottleneck
(~19k villagers: TPS 9 -> 20)
- MasterCommand: add 'fine sharded on|off' toggle and status display
- Add environment setup/launch scripts
