Add initial first test screen

ArtisanConnect/app/_layout.tsx

@@ -1,5 +1,17 @@
 import { Stack } from "expo-router";
+import { Appearance } from "react-native";
+import {Colors} from "@/constants/Colors"
 
 export default function RootLayout() {
-  return <Stack />;
+  const colorScheme = Appearance.getColorScheme();
+
+  const theme = colorScheme === 'dark' ? Colors.dark :
+   Colors.light;
+  return <Stack screenOptions={{ headerStyle: {backgroundColor:theme.background},
+  headerTintColor: theme.text
+}}>
+<Stack.Screen name="index"/>
+<Stack.Screen name="+not-found" options={{headerShown:false}}/>
+
+</Stack>;
 }