feat(sprint-13.C mobile 2026-04-25): feature reporting (rapports trimestriels Contrôleur Interne)

Mobile mirror du backend P2-NEW-3. DRY strict — Clean Architecture identique aux autres features (compliance, devise).

Domain
- StatutRapport enum (draft, signe, archive, inconnu) + extension StatutRapportX (code/libelle/severite/fromCode)
- RapportTrimestriel entity (Equatable) + helpers libellePeriode, scoreSeverite (>=80 success, >=60 warning, <60 danger)

Data
- RapportTrimestrielModel.fromJson (parsing tolérant null + dates ISO)
- ReportingRemoteDataSourceImpl (Dio) : lister/generer/signer/archiver/telechargerPdf
- ReportingRepositoryImpl @Injectable

Presentation
- ReportingBloc : Load/Generer/Signer/Archiver events, 4 states (Initial/Loading/Loaded/Error)
- RapportsTrimestrielsPage : Material 3 ListView avec cards (period, score coloré, tag statut, hash tronqué) + EmptyView + ErrorView

Tests (10/10 verts)
- StatutRapportX × 2 (fromCode parse/null/inconnu, libelle/severite/code)
- RapportTrimestriel × 5 (libellePeriode, estDraft/estSigne/estArchive, scoreSeverite × 3)
- RapportTrimestrielModel.fromJson × 3 (complet, fallbacks, date invalide)

Note : viewer PDF interne reporté à un sprint dédié (intégration pdfx + permission storage Android). Téléchargement bytes via API exposé dans datasource pour usage futur.

lib/features/reporting/data/repositories/reporting_repository_impl.dart

@@ -0,0 +1,29 @@
+import 'package:injectable/injectable.dart';
+import '../../domain/entities/rapport_trimestriel.dart';
+import '../../domain/repositories/reporting_repository.dart';
+import '../datasources/reporting_remote_datasource.dart';
+
+@Injectable(as: ReportingRepository)
+class ReportingRepositoryImpl implements ReportingRepository {
+  final ReportingRemoteDataSource remote;
+  ReportingRepositoryImpl(this.remote);
+
+  @override
+  Future<List<RapportTrimestriel>> lister({String? orgId, int? annee}) =>
+      remote.lister(orgId: orgId, annee: annee);
+
+  @override
+  Future<RapportTrimestriel> generer({String? orgId, required int annee, required int trimestre}) =>
+      remote.generer(orgId: orgId, annee: annee, trimestre: trimestre);
+
+  @override
+  Future<RapportTrimestriel> signer(String id, String signataireId) =>
+      remote.signer(id, signataireId);
+
+  @override
+  Future<RapportTrimestriel> archiver(String id) =>
+      remote.archiver(id);
+
+  @override
+  Future<List<int>> telechargerPdf(String id) => remote.telechargerPdf(id);
+}