feat: migrate Firebase → NestJS REST API backend

Replace all Firebase SDK (Auth, Firestore, Storage) with HTTP calls
to backend.prosapp.co/api/v1:

- New ApiService singleton (JWT token, GET/POST/PATCH/DELETE/upload)
- auth_provider: Firebase Auth → /auth/login, /auth/register, /auth/phone/*
- services_provider + calendar_services_provider → /services endpoints
- professional_provider + professionals_provider → /professional-info, /users/professionals
- profile_form_provider + professional_form_provider → /users/me, /storage/upload
- cities/professions/settings providers → /cities, /professions, /settings
- firebase_chat_repository → polling via /chats endpoints (3s interval)
- firebase_score_repository → polling via /comments endpoints (10s interval)
- professional_detail_provider → /users/:id + /professional-info/:id
- dashboard_view: Firestore.add → POST /services
- chat_view + rating_view: FirebaseAuth.uid → AuthProvider.user.id
- Models: Timestamp → String for createdAt fields
- google_fonts upgraded to ^8.1.0 (Dart 3.12 compat)
- Remove firebase_core, firebase_auth, cloud_firestore, firebase_storage from pubspec

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

lib/providers/professional_detail_provider.dart

@@ -1,43 +1,27 @@
-import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:flutter/material.dart';
-import 'package:prosapp_web_app/models/comment_entity.dart';
 import 'package:prosapp_web_app/models/profesional.dart';
 import 'package:prosapp_web_app/models/usuario.dart';
 import 'package:prosapp_web_app/models/usuario_profesional.dart';
+import 'package:prosapp_web_app/services/api_service.dart';
 
 class ProfessionalDetailProvider extends ChangeNotifier {
   UsuarioProfesional? professional;
   bool isLoading = true;
+  final _api = ApiService.instance;
 
   Future<void> getProfessionalById(String uid) async {
     try {
       isLoading = true;
       notifyListeners();
 
-      final userDoc =
-          await FirebaseFirestore.instance.collection('users').doc(uid).get();
+      final userData = await _api.get('/users/$uid');
+      final user = Usuario.fromDocument(userData as Map<String, dynamic>);
 
-      if (!userDoc.exists) {
-        print('Profesional no encontrado.');
-        return;
-      }
+      final proData = await _api.get('/professional-info/$uid');
+      final professionalInfo = Profesional.fromDocument(proData as Map<String, dynamic>);
 
-      final user = Usuario.fromDocument(userDoc.data()!);
-
-      final professionalDoc = await FirebaseFirestore.instance
-          .collection('professional_info')
-          .doc(uid)
-          .get();
-
-      if (!professionalDoc.exists) {
-        print('Información profesional no encontrada.');
-        return;
-      }
-
-      final professionalInfo =
-          Profesional.fromDocument(professionalDoc.data()!);
-
-      final averageScore = await _getAverageScore(uid);
+      final repData = await _api.get('/comments/reputation/$uid');
+      final averageScore = (repData['average'] as num?)?.toDouble() ?? 0.0;
 
       professional = UsuarioProfesional(
         user: user,
@@ -51,22 +35,4 @@ class ProfessionalDetailProvider extends ChangeNotifier {
       notifyListeners();
     }
   }
-
-  Future<double> _getAverageScore(String userId) async {
-    final querySnapshot = await FirebaseFirestore.instance
-        .collection('comments')
-        .where('destination_id', isEqualTo: userId)
-        .where('is_from_user', isEqualTo: true)
-        .get();
-
-    if (querySnapshot.docs.isEmpty) {
-      return 0.0;
-    }
-
-    final scores = querySnapshot.docs
-        .map((e) => CommentEntity.fromDocument(e.data()).score)
-        .toList();
-    final averageScore = scores.reduce((a, b) => a + b) / scores.length;
-    return averageScore;
-  }
 }