feat: half update

tests/helpers/gridmap_mock.gd

@@ -8,6 +8,16 @@ var cell_size := Vector3(1, 1, 1)
 var cells: Dictionary = {} # Vector3i -> item id
 var astar_inits := 0
 
+# Walkable-tile set. Items in this list are passable for the bot planner.
+# By default everything is walkable except the items the bot calls out
+# explicitly via `non_walkable_items`.
+var non_walkable_items: Array[int] = []
+var columns: int = 20
+var rows: int = 20
+
+func is_position_valid(pos: Vector2i) -> bool:
+	return pos.x >= 0 and pos.x < columns and pos.y >= 0 and pos.y < rows
+
 func set_cell_item(pos: Vector3i, item: int, _orientation: int = 0) -> void:
 	if item == -1:
 		cells.erase(pos)