feat: Add foundational UI components, pages, and theme management for the e-learning application.

Frontend-Learner/components/layout/AppHeader.vue

@@ -0,0 +1,81 @@
+<script setup lang="ts">
+/**
+ * @file AppHeader.vue
+ * @description The main header for the authenticated application dashboard.
+ * Uses Quasar QToolbar.
+ */
+
+defineProps<{
+  /** Controls visibility of the search bar */
+  showSearch?: boolean
+}>()
+
+const emit = defineEmits<{
+  /** Emitted when the hamburger menu is clicked */
+  toggleSidebar: []
+}>()
+
+const searchText = ref('')
+</script>
+
+<template>
+  <q-toolbar class="bg-transparent text-slate-800 dark:text-white h-16 px-4">
+    <!-- Mobile Menu Toggle -->
+    <q-btn
+      flat
+      round
+      dense
+      icon="menu"
+      @click="emit('toggleSidebar')"
+      class="md:hidden mr-2 text-slate-700 dark:text-white"
+      aria-label="Menu"
+    />
+
+    <!-- Branding -->
+    <div class="flex items-center gap-2 cursor-pointer" @click="navigateTo('/dashboard')">
+      <div class="w-8 h-8 rounded-lg bg-blue-600 flex items-center justify-center text-white font-bold">
+        E
+      </div>
+      <span class="font-bold text-xl text-blue-600 dark:text-blue-400 hidden xs:block">e-Learning</span>
+    </div>
+    
+    <q-space />
+    
+    <!-- Center Search (Optional) -->
+    <div v-if="showSearch !== false" class="hidden md:block w-1/3 max-w-md mx-4">
+      <q-input
+        dense
+        outlined
+        rounded
+        v-model="searchText"
+        :placeholder="$t('menu.searchCourses')"
+        class="bg-slate-50 dark:bg-slate-700/50 search-input"
+        bg-color="transparent" 
+      >
+        <template v-slot:prepend>
+          <q-icon name="search" class="text-slate-400" />
+        </template>
+      </q-input>
+    </div>
+    
+    <q-space />
+
+    <!-- Right Actions -->
+    <div class="flex items-center gap-2">
+      <!-- Language Switcher -->
+      <LanguageSwitcher />
+      
+      <!-- User Profile Dropdown -->
+      <UserMenu />
+    </div>
+  </q-toolbar>
+</template>
+
+<style scoped>
+.search-input :deep(.q-field__control) {
+  border-radius: 9999px; /* Full rounded */
+}
+.search-input :deep(.q-field__control:before) {
+  border-color: #e2e8f0; /* slate-200 */
+}
+</style>