refactor: extract grid abstraction for reuse

internal/position/position.go

@@ -0,0 +1,27 @@
+// Package position provides types and functions to represent and manipulate positions and moves on a 2D grid.
+package position
+
+type Position interface {
+	Row() int
+	Column() int
+}
+
+type position struct {
+	row    int
+	column int
+}
+
+func From(row int, column int) Position {
+	return position{
+		row:    row,
+		column: column,
+	}
+}
+
+func (p position) Row() int {
+	return p.row
+}
+
+func (p position) Column() int {
+	return p.column
+}