enhance Google OAuth handling by adding deep link redirect support; update comments for clarity

src/AUTH/GoogleAUTH.js

@@ -6,10 +6,9 @@ WebBrowser.maybeCompleteAuthSession();
 
 const GOOGLE_CLIENT_ID = '313090284964-rgq1u7np6ogucu9o97s134n5nc6nj7kf.apps.googleusercontent.com';
 
-// makeRedirectUri uses the scheme from app.json ("media-aggregation") to build
-// the deep link URI that Android will route back into the app after OAuth.
-// The resulting URI is: media-aggregation://  (registered in Google Cloud Console)
-// For Expo Go dev testing the loopback http://localhost is used instead.
+// Builds the deep link redirect URI from the scheme defined in app.json ("media-aggregation").
+// On an Android APK this resolves to: media-aggregation://
+// Register this URI in Google Cloud Console → Authorized redirect URIs.
 const REDIRECT_URI = AuthSession.makeRedirectUri({ scheme: 'media-aggregation' });
 
 const GOOGLE_DISCOVERY = {
@@ -91,7 +90,7 @@ class GoogleAUTH extends AuthServiceBase {
       return {
         success: true,
         accessToken: this.accessToken,
-        refreshToken: null,
+        refreshToken: this.refreshToken,
         email: this.email,
       };
     } catch (error) {