Restructure tile size usage

scripts/autoloads/battle_map_helper.gd

@@ -0,0 +1,17 @@
+extends Node
+
+var TILE_SIZE: float:
+	get:
+		return BattleMapConstants.TILE_SIZE
+
+
+func snap_to_grid(pos: Vector2) -> Vector2:
+	return Vector2(floorf(pos.x / TILE_SIZE), floorf(pos.y / TILE_SIZE)) * TILE_SIZE
+
+
+func world_to_coords(pos: Vector2) -> Vector2i:
+	return Vector2i(snap_to_grid(pos) / TILE_SIZE)
+
+
+func coords_to_world(coords: Vector2i) -> Vector2:
+	return Vector2(coords) * TILE_SIZE