Wire season flow: map screen, progress save, win recording, next stage

SaveRepository (versioned JSON over prefs) with best-result merging and
unlock walking; ContentRepository loads the bundled pack; SeasonFlow/
Progress notifiers orchestrate stage start -> win record -> advance.
Season map grid with stars/locks, Home -> Map -> Game navigation,
close button, next-stage action on the win overlay.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/state/progress_notifier.dart

@@ -0,0 +1,28 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../data/save_repository.dart';
+import 'providers.dart';
+
+/// Exposes saved progress as immutable state so screens rebuild when stars
+/// land; persistence goes through [SaveRepository].
+class ProgressNotifier extends Notifier<Map<String, StageProgress>> {
+  @override
+  Map<String, StageProgress> build() =>
+      ref.read(saveRepositoryProvider).snapshot();
+
+  Future<void> record({
+    required String seasonId,
+    required String stageId,
+    required int stars,
+    required int score,
+  }) async {
+    final repo = ref.read(saveRepositoryProvider);
+    await repo.recordResult(
+      seasonId: seasonId,
+      stageId: stageId,
+      stars: stars,
+      score: score,
+    );
+    state = repo.snapshot();
+  }
+}

lib/state/providers.dart

@@ -1,7 +1,12 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../data/content_repository.dart';
+import '../data/save_repository.dart';
+import '../game/models/season.dart';
 import '../services/audio_service.dart';
 import 'game_session_notifier.dart';
+import 'progress_notifier.dart';
+import 'season_flow_notifier.dart';
 
 final gameSessionProvider =
     NotifierProvider<GameSessionNotifier, GameViewState?>(
@@ -13,3 +18,24 @@ final audioServiceProvider = Provider<AudioService>((ref) {
   ref.onDispose(service.dispose);
   return service;
 });
+
+/// Overridden with the opened repository in main() (and in tests).
+final saveRepositoryProvider = Provider<SaveRepository>(
+  (ref) => throw UnimplementedError('override with an opened SaveRepository'),
+);
+
+final progressProvider =
+    NotifierProvider<ProgressNotifier, Map<String, StageProgress>>(
+  ProgressNotifier.new,
+);
+
+final seasonFlowProvider = NotifierProvider<SeasonFlowNotifier, SeasonFlow?>(
+  SeasonFlowNotifier.new,
+);
+
+final contentRepositoryProvider =
+    Provider<ContentRepository>((ref) => ContentRepository());
+
+final seasonsProvider = FutureProvider<List<SeasonPack>>(
+  (ref) => ref.read(contentRepositoryProvider).availableSeasons(),
+);

lib/state/season_flow_notifier.dart

@@ -0,0 +1,44 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../game/models/season.dart';
+import '../game/models/stage.dart';
+import 'providers.dart';
+
+class SeasonFlow {
+  const SeasonFlow({required this.pack, required this.index});
+
+  final SeasonPack pack;
+  final int index;
+
+  StageConfig get stage => pack.stages[index];
+  bool get hasNext => index + 1 < pack.stages.length;
+}
+
+/// Orchestrates which season stage is being played: starting stages,
+/// recording wins, advancing to the next stage.
+class SeasonFlowNotifier extends Notifier<SeasonFlow?> {
+  @override
+  SeasonFlow? build() => null;
+
+  void startSeasonStage(SeasonPack pack, int index) {
+    state = SeasonFlow(pack: pack, index: index);
+    ref.read(gameSessionProvider.notifier).startStage(pack.stages[index]);
+  }
+
+  Future<void> recordWin({required int stars, required int score}) async {
+    final flow = state;
+    if (flow == null) return;
+    await ref.read(progressProvider.notifier).record(
+          seasonId: flow.pack.seasonId,
+          stageId: flow.stage.id,
+          stars: stars,
+          score: score,
+        );
+  }
+
+  void nextStage() {
+    final flow = state;
+    if (flow == null || !flow.hasNext) return;
+    startSeasonStage(flow.pack, flow.index + 1);
+  }
+}