Stage 4: guided Player for both Modes and the Session summary

- buildSegments lays a Plan out as holds with Transitions (get ready,
  switch sides, next round, next exercise) or sets with count-up Rests;
  Supersets alternate members and rest per round unless asked otherwise
- SessionRunner drives segments against an injected clock: auto-advance
  with a chime, pause, skip, back, rep sets confirmed with logged reps
  and kg, timed sets started on demand, early end
- Player screen: countdown ring, accent pulse in the last 3 s, Flip
  Animation, next-up cards, Rest Screen, mute toggle, screen kept on
- Sessions table (schema v2 migration) keeps a Plan snapshot and Set
  Logs; nothing is saved when no hold or set was done
- Summary with time, exercises or sets logged, and every Set Log
- Synthesised quiet cue sounds (tools/sounds), status bar per Mode

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/history/session_repository_test.dart

@@ -0,0 +1,58 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zenxercise/src/database/database.dart';
+import 'package:zenxercise/src/history/session_repository.dart';
+import 'package:zenxercise/src/modes/mode.dart';
+import 'package:zenxercise/src/plans/models/plan.dart';
+import 'package:zenxercise/src/player/session_runner.dart';
+
+import '../support/test_database.dart';
+
+void main() {
+  late AppDatabase db;
+  late SessionRepository sessions;
+
+  setUp(() {
+    db = testDatabase();
+    sessions = SessionRepository(db);
+  });
+  tearDown(() => db.close());
+
+  Plan plan(Mode mode) => Plan(
+    id: 'p1',
+    mode: mode,
+    name: 'Legs',
+    items: const [WorkoutStep(exerciseId: 'Squat', sets: 1, target: WorkoutTarget.reps(10))],
+    createdAt: DateTime(2026),
+    updatedAt: DateTime(2026),
+  );
+
+  SessionResult result(Mode mode, DateTime end, {bool complete = true}) => SessionResult(
+    plan: plan(mode),
+    startedAt: end.subtract(const Duration(minutes: 30)),
+    endedAt: end,
+    duration: const Duration(minutes: 28),
+    complete: complete,
+    setLogs: const [SetLog(exerciseId: 'Squat', set: 1, reps: 8, weightKg: 60)],
+  );
+
+  test('a saved Session keeps its Plan snapshot, logs and outcome', () async {
+    final saved = await sessions.save(result(Mode.workout, DateTime(2026, 10, 29, 19), complete: false));
+
+    expect(saved.planName, 'Legs');
+    expect(saved.items.single, isA<WorkoutStep>());
+    expect(saved.duration, const Duration(minutes: 28));
+    expect(saved.complete, isFalse);
+    expect(saved.setLogs.single.reps, 8);
+    expect(saved.setLogs.single.weightKg, 60);
+  });
+
+  test('Sessions are listed per Mode, the latest first', () async {
+    await sessions.save(result(Mode.workout, DateTime(2026, 10, 28)));
+    await sessions.save(result(Mode.workout, DateTime(2026, 10, 29)));
+    await sessions.save(result(Mode.stretching, DateTime(2026, 10, 30)));
+
+    final workout = await sessions.watchSessions(Mode.workout).first;
+
+    expect(workout.map((s) => s.endedAt.day), [29, 28]);
+  });
+}