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/ui/screens/game_screen.dart

@@ -2,7 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../game/engine/game_engine.dart';
-import '../../game/models/stage.dart';
 import '../../l10n/gen/app_localizations.dart';
 import '../../services/audio_service.dart';
 import '../../state/game_session_notifier.dart';
@@ -15,29 +14,8 @@ import '../widgets/hud_widget.dart';
 import '../widgets/piece_painter.dart';
 import '../widgets/tray_widget.dart';
 
-/// Demo stage until the season map lands in Phase 3.
-final _demoStage = StageConfig.fromJson({
-  'id': 'demo_001',
-  'seed': 20260611,
-  'moveLimit': 25,
-  'preset': [
-    {'x': 2, 'y': 2, 't': 'gem'},
-    {'x': 5, 'y': 2, 't': 'gem'},
-    {'x': 2, 'y': 5, 't': 'gem'},
-    {'x': 5, 'y': 5, 't': 'gem'},
-    {'x': 3, 'y': 7, 't': 'filled', 'c': 1},
-    {'x': 4, 'y': 7, 't': 'filled', 'c': 1},
-  ],
-  'objectives': [
-    {'type': 'clearGems', 'count': 4},
-  ],
-  'stars': {
-    'two': {'movesLeft': 6},
-    'three': {'movesLeft': 12},
-  },
-  'generatorProfile': 'mid',
-});
-
+/// Renders whatever session [gameSessionProvider] holds; callers start the
+/// stage (via SeasonFlowNotifier) before navigating here.
 class GameScreen extends ConsumerStatefulWidget {
   const GameScreen({super.key});
 
@@ -55,16 +33,6 @@ class _GameScreenState extends ConsumerState<GameScreen> {
   /// How far the dragged piece floats above the finger so it stays visible.
   static const double _lift = 70;
 
-  @override
-  void initState() {
-    super.initState();
-    WidgetsBinding.instance.addPostFrameCallback((_) {
-      if (ref.read(gameSessionProvider) == null) {
-        ref.read(gameSessionProvider.notifier).startStage(_demoStage);
-      }
-    });
-  }
-
   RenderBox? get _boardBox =>
       _boardKey.currentContext?.findRenderObject() as RenderBox?;
 
@@ -125,7 +93,7 @@ class _GameScreenState extends ConsumerState<GameScreen> {
     }
   }
 
-  void _playSfx(GameViewState? prev, GameViewState? next) {
+  void _onSessionChange(GameViewState? prev, GameViewState? next) {
     if (next == null) return;
     final audio = ref.read(audioServiceProvider);
     if (prev?.fxTick != next.fxTick && next.lastPlacement != null) {
@@ -137,14 +105,20 @@ class _GameScreenState extends ConsumerState<GameScreen> {
       }
     }
     if (prev?.phase != next.phase) {
-      if (next.phase == GamePhase.won) audio.play(Sfx.win);
+      if (next.phase == GamePhase.won) {
+        audio.play(Sfx.win);
+        // recordResult keeps the best run, so re-entry is harmless.
+        ref
+            .read(seasonFlowProvider.notifier)
+            .recordWin(stars: next.starsEarned, score: next.score);
+      }
       if (next.phase == GamePhase.lost) audio.play(Sfx.lose);
     }
   }
 
   @override
   Widget build(BuildContext context) {
-    ref.listen<GameViewState?>(gameSessionProvider, _playSfx);
+    ref.listen<GameViewState?>(gameSessionProvider, _onSessionChange);
     final view = ref.watch(gameSessionProvider);
     if (view == null) {
       return const Scaffold(body: Center(child: CircularProgressIndicator()));
@@ -193,6 +167,15 @@ class _GameScreenState extends ConsumerState<GameScreen> {
                 _dragIndex! < view.tray.length)
               _draggedPieceOverlay(view, draggedTopLeft, boardBox),
             if (view.phase != GamePhase.playing) _resultOverlay(view),
+            if (Navigator.of(context).canPop())
+              Positioned(
+                top: 4,
+                left: 4,
+                child: IconButton(
+                  icon: const Icon(Icons.close, color: Colors.white54),
+                  onPressed: () => Navigator.of(context).pop(),
+                ),
+              ),
           ],
         ),
       ),
@@ -219,11 +202,18 @@ class _GameScreenState extends ConsumerState<GameScreen> {
     final notifier = ref.read(gameSessionProvider.notifier);
     final theme = Theme.of(context);
 
+    final flow = ref.read(seasonFlowProvider);
     final (title, actions) = switch ((view.phase, view.stuckReason)) {
       (GamePhase.won, _) => (
           l10n.stageClear,
           [
-            FilledButton(
+            if (flow != null && flow.hasNext)
+              FilledButton(
+                onPressed:
+                    ref.read(seasonFlowProvider.notifier).nextStage,
+                child: Text(l10n.nextStage),
+              ),
+            TextButton(
               onPressed: notifier.restart,
               child: Text(l10n.playAgain),
             ),