feat: create visualizer singleton

Signed-off-by: Dasun Abeykoon <[email protected]>

Author: dabeycorn

src/main/java/org/frc6423/robot/subsystems/superstructure/Visualizer.java

@@ -0,0 +1,23 @@
+// Copyright (c) 2025 FRC 6423 - Ward Melville Iron Patriots
+// https://github.com/wmironpatriots
+// 
+// Open Source Software; you can modify and/or share it under the terms of
+// MIT license file in the root directory of this project
+
+package org.frc6423.robot.subsystems.superstructure;
+
+/** Superstructure mech2d visualizer use `Visualizer.getDefault()` to get singleton instance */
+public class Visualizer {
+  private Visualizer instance;
+
+  /**
+   * @return {@link Visualizer} singleton instance
+   */
+  public Visualizer getDefault() {
+    if (instance == null) {
+      instance = new Visualizer();
+    }
+
+    return instance;
+  }
+}