Organize game files into their project directory and ensure proper build configuration

Moves all game source files and assets into the 'American-Identity-Project' directory and updates the manifest to point to the 'Display' class as the main entry point.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: f6819c21-e85d-45ac-acde-604db2cfa4fe
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: a9500e48-7f68-408f-a5c6-28df9f59fe00
Replit-Helium-Checkpoint-Created: true

American-Identity-Project/Powerup.java

@@ -0,0 +1,24 @@
+import javax.swing.ImageIcon;
+
+public class Powerup extends Collectable {
+  int yVelo, xVelo, id;
+  boolean onGround;
+
+  public Powerup(int x, int y, int w, int h, int id) {
+    super(x, y, w, h, new ImageIcon("Sprites/Powerup" + id + ".png"));
+    xVelo = 0;
+    yVelo = -7;
+    onGround = false;
+    this.id = id;
+  }
+
+  public void moveX(int moveX) {
+    this.x += moveX;
+    this.rect.x = this.x;
+  }
+
+  public void moveY(int moveY) {
+    this.y += moveY;
+    this.rect.y = this.y;
+  }
+}