feat: Expo scaffold + auth screens + core screens (#39-#46, #48)

app/(app)/_layout.tsx

@@ -0,0 +1,41 @@
+import { Tabs } from 'expo-router';
+import { Text } from 'react-native';
+
+export default function AppLayout() {
+  return (
+    <Tabs
+      screenOptions={{
+        headerShown: false,
+        tabBarActiveTintColor: '#2563EB',
+        tabBarInactiveTintColor: '#6B7280',
+        tabBarStyle: { paddingBottom: 4 },
+      }}
+    >
+      <Tabs.Screen
+        name="dashboard"
+        options={{ title: 'Home', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>🏠</Text> }}
+      />
+      <Tabs.Screen
+        name="clients"
+        options={{ title: 'Clients', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>👥</Text> }}
+      />
+      <Tabs.Screen
+        name="payments"
+        options={{ title: 'Payments', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>💰</Text> }}
+      />
+      <Tabs.Screen
+        name="remittances"
+        options={{ title: 'Remit', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>📋</Text> }}
+      />
+      <Tabs.Screen
+        name="tickets"
+        options={{ title: 'Tickets', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>🎫</Text> }}
+      />
+      <Tabs.Screen
+        name="profile"
+        options={{ title: 'Profile', tabBarIcon: ({ color }) => <Text style={{ color, fontSize: 20 }}>👤</Text> }}
+      />
+      <Tabs.Screen name="installations" options={{ href: null }} />
+    </Tabs>
+  );
+}