Implement splash screen functionality

Adds a splash screen to improve the app's initial loading experience.

android/app/src/main/java/com/lovable/zellyfinance/MainActivity.java

@@ -1,5 +1,16 @@
+
 package com.lovable.zellyfinance;
 
+import android.os.Bundle;
 import com.getcapacitor.BridgeActivity;
+import com.getcapacitor.Plugin;
 
-public class MainActivity extends BridgeActivity {}
+public class MainActivity extends BridgeActivity {
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        
+        // 스플래시 화면 처리를 위한 추가 초기화 코드
+        registerPlugin(com.capacitorjs.plugins.splashscreen.SplashScreenPlugin.class);
+    }
+}