chore: rename Header to Navbar

src/App.vue

 <template>
   <div id="app" :key="locale" class="tw-flex tw-flex-col tw-min-h-screen">
-    <app-header :modules="modules" :user="user" />
+    <app-navbar :modules="modules" :user="user" />
 
     <div v-if="user.steeringUser !== null" class="tw-flex-1 tw-flex tw-my-8">
       <router-view :modules="modules" :user="user" />
@@ -15,7 +15,7 @@
 </template>
 
 <script setup>
-import AppHeader from './components/Header.vue'
+import AppNavbar from './components/Navbar.vue'
 import AppFooter from './components/Footer.vue'
 import Home from './Pages/Home.vue'
 import { useStore } from 'vuex'