feat: filtrar profesionales por ciudad del usuario al cargar lista

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/providers/professionals_provider.dart

@@ -5,15 +5,24 @@ import 'package:prosapp_web_app/services/api_service.dart';
 class ProfessionalsProvider extends ChangeNotifier {
   List<UsuarioProfesional> professionals = [];
   bool isLoading = true;
+  String? _city;
   final _api = ApiService.instance;
 
-  ProfessionalsProvider() {
-    getProfessionals();
+  void updateCity(String? city) {
+    if (_city != city) {
+      _city = city;
+      getProfessionals();
+    }
   }
 
   getProfessionals() async {
+    isLoading = true;
+    notifyListeners();
     try {
-      final res = await _api.get('/professionals');
+      final path = (_city != null && _city!.isNotEmpty)
+          ? '/professionals?city=${Uri.encodeComponent(_city!)}'
+          : '/professionals';
+      final res = await _api.get(path);
       final list = (res is Map ? res['data'] : res) as List;
       professionals = list
           .map((e) => UsuarioProfesional.fromDocument(e as Map<String, dynamic>))