feat: pedir nombre al primer login + avatar con iniciales

- Detectar usuario nuevo (nombre == telefono) y redirigir
  a pantalla setup-name antes del dashboard
- SetupNameView: bienvenida con campo de nombre obligatorio
- AuthProvider.updateName() para guardar via PATCH /users/me
- NavbarAvatar: iniciales con color por inicial del nombre
  en lugar de no-image.jpg cuando no hay foto
- Perfil: mismo avatar de iniciales en la pantalla de perfil

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

lib/router/dashboard_handlers.dart

@@ -21,6 +21,7 @@ import 'package:prosapp_web_app/ui/views/service_view.dart';
 import 'package:prosapp_web_app/ui/views/services_history_view.dart';
 import 'package:prosapp_web_app/ui/views/services_requests_view.dart';
 import 'package:prosapp_web_app/ui/views/services_view.dart';
+import 'package:prosapp_web_app/ui/views/setup_name_view.dart';
 import 'package:prosapp_web_app/ui/views/support_view.dart';
 import 'package:provider/provider.dart';
 
@@ -40,6 +41,17 @@ class DashboardHandlers {
     },
   );
 
+  static Handler setupName = Handler(
+    handlerFunc: (context, params) {
+      final authProvider = Provider.of<AuthProvider>(context!);
+      if (authProvider.authStatus == AuthStatus.authenticated) {
+        return const SetupNameView();
+      } else {
+        return const LoginView();
+      }
+    },
+  );
+
   static Handler support = Handler(
     handlerFunc: (context, params) {
       final authProvider = Provider.of<AuthProvider>(context!);

lib/router/router.dart

@@ -17,6 +17,9 @@ class Flurorouter {
   static String dashboardRoute = "/dashboard";
   static String supportRoute = "/dashboard/support";
 
+  // Onboarding
+  static String setupNameRoute = "/dashboard/setup-name";
+
   // Users
   static String profileRoute = "/dashboard/profile";
   static String phoneRoute = "/dashboard/phone";
@@ -68,6 +71,13 @@ class Flurorouter {
       transitionType: TransitionType.none,
     );
 
+    // Onboarding
+    router.define(
+      setupNameRoute,
+      handler: DashboardHandlers.setupName,
+      transitionType: TransitionType.none,
+    );
+
     // Dashboard Routes
     router.define(
       dashboardRoute,