Dragon melee damage: reassign sub-entity IDs to be sequential from
the parent entity ID in ServerLevel::entityAdded(), so the client's
offset-based ID calculation matches the server. Previously the server's
smallId pool allocated non-sequential IDs, causing melee attacks to
target entity IDs the server didn't recognize.
End portal transition: ensure the player entity is always added to the
new level when transitioning from The End, not just for non-End
dimensions. The addEntity call was previously gated behind a
lastDimension != 1 check that also excluded it from End exits.
End Poem crash: bounds-check the WIN_GAME event's player index before
accessing localplayers[], with a fallback to prevent null dereference
when the server sends an out-of-range index.