fix(iap): address code review defects in freemium/IAP change

Fixes 9 of 10 review findings (10th requires a manual Play Console
step, no code change):

1. app.dart/banner_anuncio_superior.dart: move the top SafeArea inside
   BannerAnuncioSuperior so it only reserves status-bar height when an
   ad actually renders, restoring edge-to-edge layout for premium and
   free-unloaded users.
2. servicio_anuncios.dart: bound every interstitial await (load,
   presentation, and the injected implementation itself) with
   injectable timeouts so a callback that never fires can no longer
   hang a caller.
3. estado_entitlement.dart/hoja_premium.dart: expose a typed
   resultadoUsuario signal for purchase/restore failures and
   restore-found-nothing, with dedicated localized messages
   (compraError, restauracionSinCompras) across all 13 locales --
   never the raw developer/exception string.
4. main.dart/servicio_consentimiento.dart: add a GDPR/UMP consent flow
   (ConsentInformation/ConsentForm) that gates Mobile Ads SDK init on
   canRequestAds(); premium users never see a consent form; failures
   degrade to no ads instead of crashing or blocking startup.
6. servicio_anuncios.dart: track real ad presentation
   (onAdShowedFullScreenContent) so a failed-to-show interstitial no
   longer consumes a session cap slot.
7. banner_anuncio_superior.dart: add an explicit load-attempted guard
   so repeated didChangeDependencies (e.g. entitlement notifyListeners
   during a purchase) can only ever trigger one banner load attempt.
8. servicio_anuncios.dart: make esPremium a required constructor
   parameter, matching the hardened contract already applied to
   EstadoAlarmas/EstadoGrabacion/EstadoRadio.
9. hoja_premium.dart: add a dedicated premiumActivo localized string
   instead of reusing the equalizer's equalizerActive translation,
   across all 13 locales.

All fixes implemented RED-first (failing test before production
code). Full suite: 1261 passed, 2 pre-existing skips, 0 failures.
flutter analyze: 5 pre-existing issues only, 0 new.

[version set]

lib/widgets/hoja_premium.dart

@@ -62,12 +62,58 @@ class HojaPremium extends StatelessWidget {
               ],
             ),
             const SizedBox(height: 20),
+            // FIX 3 (code review): user-facing feedback for a failed
+            // purchase/restore, or a restore that found nothing — before
+            // this, `resultadoUsuario` had ZERO UI, so the spinner just
+            // stopped with no feedback at all. Never the raw
+            // `EventoCompra.mensaje` developer string — always the mapped,
+            // generic localized message.
+            if (entitlement.resultadoUsuario != null)
+              Padding(
+                key: const ValueKey('hoja-premium-resultado'),
+                padding: const EdgeInsets.only(bottom: 12),
+                child: Row(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    Icon(
+                      entitlement.resultadoUsuario ==
+                              ResultadoEntitlementUsuario.error
+                          ? Icons.error_outline_rounded
+                          : Icons.info_outline_rounded,
+                      size: 18,
+                      color:
+                          entitlement.resultadoUsuario ==
+                                  ResultadoEntitlementUsuario.error
+                              ? Theme.of(context).colorScheme.error
+                              : Theme.of(context).textTheme.bodyMedium?.color,
+                    ),
+                    const SizedBox(width: 8),
+                    Expanded(
+                      child: Text(
+                        entitlement.resultadoUsuario ==
+                                ResultadoEntitlementUsuario.error
+                            ? l10n.compraError
+                            : l10n.restauracionSinCompras,
+                        style: Theme.of(context).textTheme.bodyMedium,
+                      ),
+                    ),
+                    IconButton(
+                      key: const ValueKey('hoja-premium-resultado-descartar'),
+                      icon: const Icon(Icons.close_rounded, size: 18),
+                      onPressed: () => entitlement.consumirResultadoUsuario(),
+                      padding: EdgeInsets.zero,
+                      constraints: const BoxConstraints(),
+                      visualDensity: VisualDensity.compact,
+                    ),
+                  ],
+                ),
+              ),
             if (entitlement.esPremium)
               Padding(
                 key: const ValueKey('hoja-premium-activo'),
                 padding: const EdgeInsets.only(bottom: 12),
                 child: Text(
-                  l10n.equalizerActive,
+                  l10n.premiumActivo,
                   style: Theme.of(context).textTheme.bodyMedium,
                 ),
               )