Add all 23 GoF design pattern implementations

01-creational/abstract-factory/DarkButton.java

@@ -0,0 +1,11 @@
+package abstractfactory;
+public class DarkButton implements Button {
+    @Override
+    public void render() {
+        System.out.println("[Dark Button] Charcoal background, white text, no border");
+    }
+    @Override
+    public void onClick() {
+        System.out.println("[Dark Button] Bright highlight ripple effect");
+    }
+}