feat(#173): feed bulles parent branché sur GET /cards

Affiche la file d’attention pastel (assets card_*_h) filtrée
par couple courant, avec accept / refus motivé / ack.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/services/api/api_config.dart

@@ -93,6 +93,10 @@ class ApiConfig {
   static const String conversations = '/conversations';
   static const String notifications = '/notifications';
 
+  /// File d'attention / bulles (#173 / #194).
+  static const String cards = '/cards';
+  static const String cardsStream = '/cards/stream';
+
   // Headers
   static Map<String, String> get headers => {
         'Content-Type': 'application/json',

frontend/lib/services/api/cards_service.dart

@@ -0,0 +1,87 @@
+import 'dart:convert';
+
+import 'package:http/http.dart' as http;
+import 'package:p_tits_pas/models/carte_bulle.dart';
+import 'package:p_tits_pas/services/api/api_config.dart';
+import 'package:p_tits_pas/services/api/tokenService.dart';
+
+/// Accès API Cartes (file d'attention) — tickets #173 / #194.
+/// - GET    /cards?placementId=
+/// - POST   /cards/:id/respond
+class CardsService {
+  static Future<Map<String, String>> _headers() async {
+    final token = await TokenService.getToken();
+    return token != null
+        ? ApiConfig.authHeaders(token)
+        : Map<String, String>.from(ApiConfig.headers);
+  }
+
+  static String _extractError(String body, String fallback) {
+    try {
+      final decoded = jsonDecode(body);
+      if (decoded is Map<String, dynamic>) {
+        final message = decoded['message'];
+        if (message is String && message.trim().isNotEmpty) {
+          return message;
+        }
+        if (message is Map && message['message'] is String) {
+          return message['message'] as String;
+        }
+      }
+    } catch (_) {}
+    return fallback;
+  }
+
+  /// Feed de bulles pour l'utilisateur (filtré par couple / placement).
+  static Future<List<CarteBulle>> lister({String? placementId}) async {
+    final query = <String, String>{};
+    if (placementId != null && placementId.isNotEmpty) {
+      query['placementId'] = placementId;
+    }
+    final uri = Uri.parse(
+      '${ApiConfig.baseUrl}${ApiConfig.cards}',
+    ).replace(queryParameters: query.isEmpty ? null : query);
+
+    final response = await http.get(uri, headers: await _headers());
+    if (response.statusCode != 200) {
+      throw Exception(
+        _extractError(response.body, 'Erreur chargement des cartes'),
+      );
+    }
+
+    final decoded = jsonDecode(response.body);
+    final list = (decoded is Map ? decoded['items'] as List? : null) ?? const [];
+    return list
+        .whereType<Map>()
+        .map((e) => CarteBulle.fromJson(Map<String, dynamic>.from(e)))
+        .toList();
+  }
+
+  /// Répondre : accept | refuse | ack.
+  static Future<CarteBulle> repondre({
+    required String cardId,
+    required String action,
+    String? comment,
+  }) async {
+    final response = await http.post(
+      Uri.parse(
+        '${ApiConfig.baseUrl}${ApiConfig.cards}/$cardId/respond',
+      ),
+      headers: await _headers(),
+      body: jsonEncode({
+        'action': action,
+        if (comment != null && comment.trim().isNotEmpty)
+          'comment': comment.trim(),
+      }),
+    );
+
+    if (response.statusCode != 200) {
+      throw Exception(
+        _extractError(response.body, 'Erreur lors de la réponse'),
+      );
+    }
+
+    final decoded = jsonDecode(response.body);
+    return CarteBulle.fromJson(Map<String, dynamic>.from(decoded as Map));
+  }
+}