* fix: duel teams start on their own arena points, in formation
MoveInside clamped the team index with Math.Min instead of Math.Max, so
every team started on the west edge point. The formation rotation also
reused the already-rotated X when computing Y, stacking players on the
north and south edges, and the SW/NE corners swapped axes, which leaves
the corner formation pointing out of the arena.
* refactor: one start point index clamp for GetBaseStartPoint and MoveInside
The clamp was written twice, and only one copy was correct.
* refactor: leave the placement loop as it was
Only the rotation lines in the loop belong to the fix.