fix(paywall): add dismiss controls and honest premium copy

The premium sheet had no close affordance or way to defer, and its
copy only said "Función Premium" without stating what it unlocks.
Adds a header close (X) button and a "not now" secondary action so
dismissal is never harder than purchasing, and replaces the bare
title with a concrete, honest breakdown of the 5 things premium
unlocks (no ads, Android Auto, station recording, alarm vacation
ranges, unlimited alarms) plus the one-time-purchase framing. The
phone equalizer is never listed, since it stays free for everyone.
New l10n keys added to all 13 locales.

lib/l10n/gen/app_localizations_id.dart

@@ -1878,4 +1878,30 @@ class AppLocalizationsId extends AppLocalizations {
 
   @override
   String get premiumActivo => 'Premium aktif';
+
+  @override
+  String get premiumHojaTitulo => 'Buka PluriWave Premium';
+
+  @override
+  String get premiumBeneficioSinAnuncios => 'Tanpa iklan di seluruh aplikasi';
+
+  @override
+  String get premiumBeneficioAndroidAuto => 'Android Auto';
+
+  @override
+  String get premiumBeneficioGrabacion => 'Perekaman stasiun';
+
+  @override
+  String get premiumBeneficioVacaciones => 'Rentang liburan untuk alarm';
+
+  @override
+  String get premiumBeneficioAlarmasIlimitadas =>
+      'Alarm tanpa batas (paket gratis mengizinkan hingga 5)';
+
+  @override
+  String get premiumPagoUnico =>
+      'Pembelian sekali bayar, untuk selamanya. Bukan langganan.';
+
+  @override
+  String get premiumAhoraNo => 'Nanti saja';
 }