feat: add move method to position

internal/position/position_test.go

@@ -3,6 +3,7 @@ package position_test
 import (
 	"testing"
 
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/move"
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/position"
 )
 
@@ -20,3 +21,14 @@ func TestFrom(t *testing.T) {
 		t.Errorf("expected column to be %d, got %d", column, pos.Column())
 	}
 }
+
+func TestMove(t *testing.T) {
+	expectedPos := position.From(3, 4)
+	startPos := position.From(2, 4)
+
+	result := startPos.Move(move.Down)
+
+	if result != expectedPos {
+		t.Errorf("expected position to be %+v, got %+v", expectedPos, result)
+	}
+}