feat: analytics abstraction with debug backend and game event wiring

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

lib/ui/screens/game_screen.dart

@@ -160,6 +160,17 @@ class _GameScreenState extends ConsumerState<GameScreen>
           ref
               .read(seasonFlowProvider.notifier)
               .recordWin(stars: next.starsEarned, score: next.score);
+          final flow = ref.read(seasonFlowProvider);
+          if (flow != null) {
+            ref.read(analyticsProvider).stageEnd(
+                  seasonId: flow.pack.seasonId,
+                  stageId: flow.stage.id,
+                  won: true,
+                  stars: next.starsEarned,
+                  score: next.score,
+                  movesUsed: next.moveLimit - next.movesLeft,
+                );
+          }
         }
         final stackBox =
             _stackKey.currentContext?.findRenderObject() as RenderBox?;
@@ -171,8 +182,22 @@ class _GameScreenState extends ConsumerState<GameScreen>
       if (next.phase == GamePhase.lost && next.endless) {
         ref.read(endlessBestProvider.notifier).record(next.score).then((isNew) {
           if (mounted) setState(() => _endlessNewBest = isNew);
+          ref.read(analyticsProvider).endlessEnd(score: next.score, isNewBest: isNew);
         });
       }
+      if (next.phase == GamePhase.lost && !next.endless) {
+        final flow = ref.read(seasonFlowProvider);
+        if (flow != null) {
+          ref.read(analyticsProvider).stageEnd(
+                seasonId: flow.pack.seasonId,
+                stageId: flow.stage.id,
+                won: false,
+                stars: 0,
+                score: next.score,
+                movesUsed: next.moveLimit - next.movesLeft,
+              );
+        }
+      }
       if (next.phase == GamePhase.won || next.phase == GamePhase.lost) {
         ref.read(streakProvider.notifier).onStagePlayed(DateTime.now());
       }
@@ -367,7 +392,10 @@ class _GameScreenState extends ConsumerState<GameScreen>
           l10n.outOfMoves,
           [
             FilledButton(
-              onPressed: notifier.addExtraMoves,
+              onPressed: () {
+                ref.read(analyticsProvider).rescueUsed(type: 'extra_moves');
+                notifier.addExtraMoves();
+              },
               child: Text(l10n.plusFiveMoves),
             ),
             TextButton(
@@ -380,7 +408,10 @@ class _GameScreenState extends ConsumerState<GameScreen>
           l10n.boardFull,
           [
             FilledButton(
-              onPressed: notifier.useContinue,
+              onPressed: () {
+                ref.read(analyticsProvider).rescueUsed(type: 'continue');
+                notifier.useContinue();
+              },
               child: Text(l10n.watchAdContinue),
             ),
             TextButton(

lib/ui/screens/home_screen.dart

@@ -90,6 +90,7 @@ class HomeScreen extends ConsumerWidget {
                     onPressed: () {
                       if (!(ModalRoute.of(context)?.isCurrent ?? true)) return;
                       ref.read(seasonFlowProvider.notifier).clear();
+                      ref.read(analyticsProvider).endlessStart();
                       ref.read(gameSessionProvider.notifier).startStage(
                             StageConfig.endless(
                               seed: DateTime.now().millisecondsSinceEpoch,