fix unit tests. add conversation model and add unit tests to it.

app/(tabs)/_layout.tsx

@@ -2,7 +2,6 @@ import { Tabs } from 'expo-router';
 import React from 'react';
 import { Platform } from 'react-native';
 
-import { HapticTab } from '@/components/HapticTab';
 import { IconSymbol } from '@/components/ui/IconSymbol';
 import TabBarBackground from '@/components/ui/TabBarBackground';
 import { Colors } from '@/constants/Colors';
@@ -16,7 +15,6 @@ export default function TabLayout() {
       screenOptions={{
         tabBarActiveTintColor: Colors[colorScheme ?? 'light'].tint,
         headerShown: false,
-        tabBarButton: HapticTab,
         tabBarBackground: TabBarBackground,
         tabBarStyle: Platform.select({
           ios: {

app/(tabs)/explore.tsx

@@ -1,23 +0,0 @@
-import { StyleSheet, Image, Platform } from 'react-native';
-
-import { IconSymbol } from '@/components/ui/IconSymbol';
-import { Text } from '@react-navigation/elements';
-
-export default function TabTwoScreen() {
-  return (
-    <Text>Explore</Text>
-  );
-}
-
-const styles = StyleSheet.create({
-  headerImage: {
-    color: '#808080',
-    bottom: -90,
-    left: -35,
-    position: 'absolute',
-  },
-  titleContainer: {
-    flexDirection: 'row',
-    gap: 8,
-  },
-});

app/(tabs)/index.tsx

@@ -1,5 +1,5 @@
 import { LanguageSelection } from '@/components/LanguageSelection';
-import { Text } from '@react-navigation/elements';
+import { Text } from 'react-native';
 import { Image, StyleSheet, Platform } from 'react-native';
 
 export default function HomeScreen() {