Start encounter feature

scripts/grid_cell.gd

@@ -0,0 +1,39 @@
+## Represents a single 3D grid cell on the game board.
+##
+## It's a data structure for occupancy state, owner tetromino, bounds, and 
+## visual feedback.
+class_name GridCell
+extends Object
+
+# Properties
+var position: Vector3i  # Grid coordinates
+var owner: Tetromino = null  # Tetromino occupying this cell
+var bounds: AABB = AABB()  # 3D axis-aligned bounding box
+
+# Visual state
+var is_highlighted: bool = false
+var is_valid_placement: bool = true
+
+
+## Checks if the cell is currently empty.
+func is_empty() -> bool:
+	return owner == null
+
+
+## Marks the cell as occupied by a tetromino.
+func occupy(tetromino: Tetromino) -> void:
+	owner = tetromino
+
+
+## Marks the cell as empty.
+func clear() -> void:
+	owner = null
+
+
+## Returns a string representation of the cell state.
+func _to_string() -> String:
+	return "GridCell3D[pos=%v, occupied=%s, valid=%s]" % [
+		position,
+		"yes" if owner else "no",
+		"yes" if is_valid_placement else "no"
+	]