Add splash screen functionality and update build documentation

- Add VSSplashScreen component using Java Swing framework
- Display splash.png image for 3 seconds on application startup
- Scale splash screen to 40% of original size (60% reduction)
- Update CLAUDE.md with JAVA_HOME setup instructions for all platforms
- Integrate splash screen into VSMain startup sequence

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

4 files changed, 109 insertions, 0 deletions

diff --git a/CLAUDE.md b/CLAUDE.md
index ef967f8..6f0e74c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -4,6 +4,14 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Build and Development Commands
 
+**Prerequisites:**
+```bash
+# Set JAVA_HOME if not already configured
+export JAVA_HOME=/usr/lib/jvm/java-21-openjdk
+# Or on macOS with Homebrew: export JAVA_HOME=$(/usr/libexec/java_home -v 21)
+# Or on Windows: set JAVA_HOME=C:\Program Files\Eclipse Adoptium\jdk-21.0.x-hotspot
+```
+
 **Essential Commands:**
 ```bash
 # Full build (recommended)
diff --git a/src/main/java/simulator/VSMain.java b/src/main/java/simulator/VSMain.java
index 46077ec..02f3e20 100644
--- a/src/main/java/simulator/VSMain.java
+++ b/src/main/java/simulator/VSMain.java
@@ -56,6 +56,10 @@ public class VSMain {
      * @param args the arguments
      */
     public static void main(String[] args) {
+        // Show splash screen
+        VSSplashScreen splash = new VSSplashScreen();
+        splash.showSplash();
+        
         try {
             UIManager.setLookAndFeel(
                 UIManager.getCrossPlatformLookAndFeelClassName());
@@ -65,6 +69,14 @@ public class VSMain {
         javax.swing.JPopupMenu.setDefaultLightWeightPopupEnabled(false);
         VSPrefs prefs = VSDefaultPrefs.init();
         VSRegisteredEvents.init(prefs);
+        
+        // Wait for splash screen to finish before showing main window
+        try {
+            Thread.sleep(3000);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+        
         new VSMain(prefs);
     }
 }
diff --git a/src/main/java/simulator/VSSplashScreen.java b/src/main/java/simulator/VSSplashScreen.java
new file mode 100644
index 0000000..d8e97d6
--- /dev/null
+++ b/src/main/java/simulator/VSSplashScreen.java
@@ -0,0 +1,89 @@
+package simulator;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import javax.imageio.ImageIO;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Splash screen for the DS-Sim application
+ * 
+ * @author Paul C. Buetow
+ */
+public class VSSplashScreen extends JWindow {
+    private static final int DISPLAY_TIME = 3000; // 3 seconds
+    
+    /**
+     * Creates and shows the splash screen
+     */
+    public VSSplashScreen() {
+        initSplashScreen();
+    }
+    
+    /**
+     * Initialize the splash screen components
+     */
+    private void initSplashScreen() {
+        try {
+            // Load the splash image from resources
+            InputStream imageStream = getClass().getResourceAsStream("/splash.png");
+            if (imageStream == null) {
+                // Fallback if image not found
+                showTextSplash();
+                return;
+            }
+            
+            BufferedImage splashImage = ImageIO.read(imageStream);
+            
+            // Reduce size by 60% (scale to 40% of original)
+            int scaledWidth = (int)(splashImage.getWidth() * 0.4);
+            int scaledHeight = (int)(splashImage.getHeight() * 0.4);
+            
+            Image scaledImage = splashImage.getScaledInstance(scaledWidth, scaledHeight, Image.SCALE_SMOOTH);
+            ImageIcon splashIcon = new ImageIcon(scaledImage);
+            
+            JLabel splashLabel = new JLabel(splashIcon);
+            splashLabel.setHorizontalAlignment(JLabel.CENTER);
+            
+            getContentPane().add(splashLabel, BorderLayout.CENTER);
+            
+            // Set window properties
+            setSize(scaledWidth, scaledHeight);
+            setLocationRelativeTo(null); // Center on screen
+            
+        } catch (IOException e) {
+            // Fallback to text splash if image loading fails
+            showTextSplash();
+        }
+    }
+    
+    /**
+     * Fallback text-based splash screen
+     */
+    private void showTextSplash() {
+        JLabel textLabel = new JLabel("DS-Sim", JLabel.CENTER);
+        textLabel.setFont(new Font("Arial", Font.BOLD, 24));
+        textLabel.setPreferredSize(new Dimension(300, 100));
+        
+        getContentPane().add(textLabel, BorderLayout.CENTER);
+        setSize(300, 100);
+        setLocationRelativeTo(null);
+    }
+    
+    /**
+     * Shows the splash screen for the specified duration
+     */
+    public void showSplash() {
+        setVisible(true);
+        
+        // Use a timer to hide the splash screen after the specified time
+        Timer timer = new Timer(DISPLAY_TIME, e -> {
+            setVisible(false);
+            dispose();
+        });
+        timer.setRepeats(false);
+        timer.start();
+    }
+}
\ No newline at end of file
diff --git a/src/main/resources/splash.png b/src/main/resources/splash.png
new file mode 100644
index 0000000..c40c314
--- /dev/null
+++ b/src/main/resources/splash.png