refactor: extract grid abstraction for reuse

cmd/01/direction/direction_test.go

@@ -0,0 +1,17 @@
+package direction_test
+
+import (
+	"testing"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/cmd/01/direction"
+)
+
+func TestDirectionConstants(t *testing.T) {
+	if direction.Left != "L" {
+		t.Errorf("Expected Left to be 'L', got '%s'", direction.Left)
+	}
+
+	if direction.Right != "R" {
+		t.Errorf("Expected Right to be 'R', got '%s'", direction.Right)
+	}
+}