Incorrect (global helper resolution):

// app/components/user-profile.gjs
<template>
  <div class="profile">
    <h1>{{capitalize @user.name}}</h1>
    <p>Joined: {{format-date @user.createdAt}}</p>
    <p>Posts: {{pluralize @user.postCount "post"}}</p>
  </div>
</template>