build(android): wire Capacitor Preferences and Firebase for push testing

Register @capacitor/preferences in the Android Capacitor project so
notification deviceId storage matches iOS. Replace the placeholder
google-services.json with the production Firebase client config for FCM.
Refresh package-lock after native sync / install.

android/app/capacitor.build.gradle

@@ -15,6 +15,7 @@ dependencies {
     implementation project(':capacitor-camera')
     implementation project(':capacitor-clipboard')
     implementation project(':capacitor-filesystem')
+    implementation project(':capacitor-preferences')
     implementation project(':capacitor-push-notifications')
     implementation project(':capacitor-share')
     implementation project(':capacitor-status-bar')