Co-authored-by: MENDOZA BALLARDO GAEL RICARDO <gael-meb123@users.noreply.github.com>

Co-authored-by: Azareth-Tr <Azareth-Tr@users.noreply.github.com>
Co-authored-by: eddgranados12 <eddgranados12@users.noreply.github.com>

primeras vistas para el frontend, configuracion para firebase

views/lib/screens/main_shell.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+import '../widgets/widgets.dart' as w;
+import 'map_screen.dart';
+import 'alerts_screen.dart';
+import 'house_screen.dart';
+import 'profile_screen.dart';
+
+class MainShell extends StatefulWidget {
+  const MainShell({super.key});
+
+  @override
+  State<MainShell> createState() => _MainShellState();
+}
+
+class _MainShellState extends State<MainShell> {
+  int _currentIndex = 0;
+
+  final List<Widget> _screens = const [
+    MapScreen(),
+    AlertsScreen(),
+    MyHouseScreen(),
+    ProfileScreen(),
+  ];
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: IndexedStack(
+        index: _currentIndex,
+        children: _screens,
+      ),
+      bottomNavigationBar: w.AppBottomNav(
+        currentIndex: _currentIndex,
+        onTap: (i) => setState(() => _currentIndex = i),
+      ),
+    );
+  }
+}