feat: migrate prosappco from Firebase to NestJS REST API (Fase 2)

- Replace all Firebase* repositories with Api* repositories using HTTP + SharedPreferences JWT
- Remove Firebase.initializeApp() and firebase_messaging background handler from main.dart
- Update DI (app_di.dart) to inject Api* repositories instead of Firebase* ones
- Replace all Timestamp/cloud_firestore usage with ISO 8601 String dates
- Stub PhoneVerificationService (Firebase phone OTP → backend OTP when implemented)
- Add ApiService singleton with JWT management in lib/services/
- Legacy firebase_*_repository.dart files preserved for Fase 4 cleanup

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

lib/screens/score/score_screen.dart

@@ -1,5 +1,3 @@
-import 'package:cloud_firestore/cloud_firestore.dart';
-import 'package:firebase_auth/firebase_auth.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -33,7 +31,7 @@ class _ScoreScreenState extends State<ScoreScreen> {
     super.initState();
     _userInfoFuture = _getUserAndProfessionalInfo(widget.service);
     isProfessional =
-        FirebaseAuth.instance.currentUser!.uid == widget.service.userId
+        ApiUserRepository.currentUserId ?? '' == widget.service.userId
             ? true
             : false;
 
@@ -304,33 +302,33 @@ class _ScoreScreenState extends State<ScoreScreen> {
                     return FilledButton(
                       onPressed: () {
                         final CommentEntity comment = widget.service.userId ==
-                                FirebaseAuth.instance.currentUser!.uid
+                                ApiUserRepository.currentUserId ?? ''
                             ? CommentEntity(
                                 serviceId: widget.service.id!,
                                 authorId:
-                                    FirebaseAuth.instance.currentUser!.uid,
+                                    ApiUserRepository.currentUserId ?? '',
                                 isFromUser: true,
                                 score: _rating,
                                 destinationId: widget.service.professionalId,
                                 content: commentController.text.trim(),
-                                createdAt: Timestamp.now(),
+                                createdAt: DateTime.now().toIso8601String(),
                               )
                             : CommentEntity(
                                 serviceId: widget.service.id!,
                                 authorId:
-                                    FirebaseAuth.instance.currentUser!.uid,
+                                    ApiUserRepository.currentUserId ?? '',
                                 isFromUser: false,
                                 score: _rating,
                                 destinationId: widget.service.userId,
                                 content: commentController.text.trim(),
-                                createdAt: Timestamp.now(),
+                                createdAt: DateTime.now().toIso8601String(),
                               );
 
                         BlocProvider.of<ScoreBloc>(context)
                             .add(SendScoreEvent(comment: comment));
 
                         if (widget.service.userId ==
-                            FirebaseAuth.instance.currentUser!.uid) {
+                            ApiUserRepository.currentUserId ?? '') {
                           context.read<ServiceBloc>().add(
                               UpdateProfessionalScored(widget.service.id!));
                         } else {
@@ -392,11 +390,11 @@ class _ScoreScreenState extends State<ScoreScreen> {
 
   Future<List<dynamic>> _getUserAndProfessionalInfo(
       ServiceEntity service) async {
-    final userRepo = FirebaseUserRepository(FirebaseAuth.instance);
+    final userRepo = Injector.appInstance.get<UserRepository>();
 
     final MyUser? userInfo;
 
-    if (FirebaseAuth.instance.currentUser!.uid == service.userId) {
+    if (ApiUserRepository.currentUserId ?? '' == service.userId) {
       userInfo = await userRepo.getMyUser(service.professionalId);
     } else {
       userInfo = await userRepo.getMyUser(service.userId);