refactor(simulation): apply rustfmt formatting

Formatting-only changes across server source and test files.
No logic changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/simulation/movement.rs

@@ -917,12 +917,14 @@ mod tests {
 
         // Entity with lower bits processes first and claims the target
         assert_eq!(
-            pos_lower, target,
+            pos_lower,
+            target,
             "entity with lower Entity::to_bits() ({}) should win the tile",
             lower.to_bits()
         );
         assert_eq!(
-            pos_higher, higher_origin,
+            pos_higher,
+            higher_origin,
             "entity with higher Entity::to_bits() ({}) should stay at origin",
             higher.to_bits()
         );