fix: remove get package, upgrade Flutter 3.44 compat deps

- Remove `get` package (incompatible with Flutter 3.44/Dart 3.12 due to
  removed ThemeData.backgroundColor and final IconData class)
- Replace GetMaterialApp → MaterialApp with GlobalKey navigatorKey
- Convert AuthenticationRepository and all 7 controllers from
  GetxController to plain singletons
- Replace Get.snackbar/offAll/to/back/defaultDialog with app_navigator
  helpers and native Flutter APIs
- Add ApiService.baseUrl static + parseJson method
- Add UserModel.getUser static method
- Add UserProvider.score via ScoresModel API
- Fix user?.photo → user?.picture in drawer_menu, service_after
- Fix logout(uid!) → logout() in drawer_menu
- Fix photo_view_web.dart missing dart:typed_data import
- Remove getCoordsOfCity call from ubicacion.dart
- Fix UserModel.getUser?.name null-safety in map/service.dart
- Upgrade: google_maps_flutter ^2.9.0, url_launcher ^6.3.0,
  font_awesome_flutter ^10.8.0, image_picker ^1.1.2

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

lib/main.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:get/get.dart';
 import 'package:intl/date_symbol_data_local.dart';
 import 'package:prosappco/src/authentication/authentication_repository.dart';
 import 'package:prosappco/src/presentation/screens/service_web.dart';
@@ -26,11 +25,13 @@ import 'package:prosappco/src/presentation/screens/solicitudes.dart';
 import 'package:flutter/foundation.dart' show kIsWeb;
 import 'package:provider/provider.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:prosappco/src/utils/app_navigator.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
 
-  Get.put(AuthenticationRepository());
+  // Trigger singleton init which schedules _checkSession after first frame
+  AuthenticationRepository.instance;
 
   await initializeDateFormatting('es_MX', null);
 
@@ -51,7 +52,8 @@ class MyApp extends StatelessWidget {
       providers: [
         ChangeNotifierProvider(create: (_) => UserProvider()),
       ],
-      child: GetMaterialApp(
+      child: MaterialApp(
+        navigatorKey: appNavigatorKey,
         theme: ThemeData(fontFamily: 'Poppins'),
         debugShowCheckedModeBanner: false,
         localizationsDelegates: const [