feat(ads): 네이티브 광고 적용 및 디버그 스위치 이동

android/app/build.gradle.kts

@@ -29,6 +29,10 @@ android {
         targetSdk = flutter.targetSdkVersion
         versionCode = flutter.versionCode
         versionName = flutter.versionName
+
+        manifestPlaceholders["admobAppId"] =
+            project.findProperty("ADMOB_APP_ID")
+                ?: "ca-app-pub-3940256099942544~3347511713"
     }
 
     buildTypes {

android/app/src/main/AndroidManifest.xml

@@ -21,6 +21,9 @@
         android:label="lunchpick"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">
+        <meta-data
+            android:name="com.google.android.gms.ads.APPLICATION_ID"
+            android:value="${admobAppId}" />
         <activity
             android:name=".MainActivity"
             android:exported="true"