Test persisted stable cloud ride identity lifecycle

test/cloud_ride_identity_migration_test.dart

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+import 'package:drift/native.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:motorcycle_dash/database/database.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  test('new rides receive a persisted cloudRideId independent of local id', () async {
+    final db = AppDatabase.forTesting(NativeDatabase.memory());
+    addTearDown(db.close);
+
+    final localId = await db.startRide();
+    final cloudId = await db.getCloudRideId(localId);
+
+    expect(cloudId, isNotNull);
+    expect(cloudId, startsWith('ride_'));
+    expect(cloudId, isNot(localId.toString()));
+
+    final secondLocalId = await db.startRide();
+    final secondCloudId = await db.getCloudRideId(secondLocalId);
+    expect(secondCloudId, isNot(cloudId));
+
+    // Re-reading the same local row returns the exact persisted identity.
+    expect(await db.getCloudRideId(localId), cloudId);
+  });
+
+  test('ensureCloudRideId is idempotent', () async {
+    final db = AppDatabase.forTesting(NativeDatabase.memory());
+    addTearDown(db.close);
+
+    final localId = await db.startRide();
+    final first = await db.ensureCloudRideId(localId);
+    final second = await db.ensureCloudRideId(localId);
+
+    expect(second, first);
+  });
+}