feat: Implement group management with BLoC pattern; add GroupBloc, GroupRepository, and related models

NOT FUNCTIONNAL

lib/data/models/group.dart

@@ -1,26 +1,65 @@
+import 'group_member.dart';
+
 class Group {
-  final String? id;
+  final String id; // ID obligatoire maintenant
   final String name;
-  final List<String> members;
+  final String tripId;
+  final String createdBy;
+  final DateTime createdAt;
+  final DateTime updatedAt;
+  final List<GroupMember> members;
 
   Group({
-    this.id,
+    required this.id, // Obligatoire
     required this.name,
-    required this.members,
-  });
+    required this.tripId,
+    required this.createdBy,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    List<GroupMember>? members,
+  })  : createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now(),
+        members = members ?? [];
 
-  factory Group.fromMap(Map<String, dynamic> data, String documentId) {
+  factory Group.fromMap(Map<String, dynamic> map, String id) {
     return Group(
-      id: documentId,
-      name: data['name'] ?? '',
-      members: List<String>.from(data['members'] ?? []),
+      id: id,
+      name: map['name'] ?? '',
+      tripId: map['tripId'] ?? '',
+      createdBy: map['createdBy'] ?? '',
+      createdAt: DateTime.fromMillisecondsSinceEpoch(map['createdAt'] ?? 0),
+      updatedAt: DateTime.fromMillisecondsSinceEpoch(map['updatedAt'] ?? 0),
+      members: [],
     );
   }
 
   Map<String, dynamic> toMap() {
     return {
       'name': name,
-      'members': members,
+      'tripId': tripId,
+      'createdBy': createdBy,
+      'createdAt': createdAt.millisecondsSinceEpoch,
+      'updatedAt': updatedAt.millisecondsSinceEpoch,
     };
   }
+
+  Group copyWith({
+    String? id,
+    String? name,
+    String? tripId,
+    String? createdBy,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    List<GroupMember>? members,
+  }) {
+    return Group(
+      id: id ?? this.id,
+      name: name ?? this.name,
+      tripId: tripId ?? this.tripId,
+      createdBy: createdBy ?? this.createdBy,
+      createdAt: createdAt ?? this.createdAt,
+      updatedAt: updatedAt ?? this.updatedAt,
+      members: members ?? this.members,
+    );
+  }
 }