feat: implement mobile reader

- implement mobile epub reader

mobile/src/screens/SettingsScreen.tsx

@@ -9,7 +9,7 @@ import {
 import { useAuth } from "../context/AuthContext";
 
 export default function SettingsScreen(): ReactNode {
-  const { state, logout } = useAuth();
+  const { user, logout } = useAuth();
 
   const handleLogout = () => {
     Alert.alert("Logout", "Are you sure you want to sign out?", [
@@ -24,11 +24,11 @@ export default function SettingsScreen(): ReactNode {
         <Text style={styles.sectionTitle}>Account</Text>
         <View style={styles.infoRow}>
           <Text style={styles.label}>Username</Text>
-          <Text style={styles.value}>{state.user?.username ?? "—"}</Text>
+          <Text style={styles.value}>{user?.username ?? "—"}</Text>
         </View>
         <View style={styles.infoRow}>
           <Text style={styles.label}>Email</Text>
-          <Text style={styles.value}>{state.user?.email ?? "—"}</Text>
+          <Text style={styles.value}>{user?.email ?? "—"}</Text>
         </View>
       </View>