Fix server-crash when teleporting across regions with negative coordinates

[KarnickelDev]

Found an issue where /tp can crash the server when teleporting across region boundaries with negative coordinates.

Reproduction

With a region size of 8, run the following commands in sequence:

/tp @s 0 80 0
/tp @s 0 80 -128.5

Cause

The crash occurs because region calculation uses an integer cast of the position. This works for positive coordinates but produces incorrect results for negative coordinates.

Using only the Z coordinate as an example (region size 8):

originLocation:  0      -> (int) 0     = region 0
targetLocation: -128.5  -> (int) -128  = region 0

ensureSync() incorrectly determines that both positions are in the same region and executes the teleport on the current thread.
However, z = -128.5 actually belongs to region -1, not region 0. So the teleport runs on the wrong thread, crashing the server.

Fix

This can be fixed by using eg. Math.floor() instead of relying on casting:
Math.floor(-128.5) = -129 = region -1
Now z=-128.5 correctly maps to region -1 and ensures that teleports across negative region boundaries are synchronized correctly.

Btw, really cool project

[PureGero]

TIL int casting is not a floor for negative numbers... Thanks Java

Thank you!