feat(ads): run consent flow (UMP->ATT->init) after the first frame

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/app.dart

@@ -1,12 +1,27 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import 'l10n/gen/app_localizations.dart';
+import 'state/providers.dart';
 import 'ui/screens/splash_screen.dart';
 
-class BlockSeasonsApp extends StatelessWidget {
+class BlockSeasonsApp extends ConsumerStatefulWidget {
   const BlockSeasonsApp({super.key});
 
+  @override
+  ConsumerState<BlockSeasonsApp> createState() => _BlockSeasonsAppState();
+}
+
+class _BlockSeasonsAppState extends ConsumerState<BlockSeasonsApp> {
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      ref.read(consentServiceProvider).ensureConsentAndInitialize();
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(