feat: Implement user profile dropdown menu with dark mode toggle and add new course browsing pages.

Frontend-Learner/pages/browse/discovery.vue

@@ -245,9 +245,9 @@ const filteredCourses = computed(() => {
 
     <!-- COURSE DETAIL VIEW: Detailed information about a specific course -->
     <div v-else>
-      <button class="btn btn-secondary mb-6" @click="showDetail = false">
-        ← กลับหน้ารายการ
-      </button>
+      <NuxtLink to="/browse" class="btn btn-secondary mb-6 inline-block">
+        ← กลับหน้ารายการคอร์ส
+      </NuxtLink>
 
       <div class="grid-12">
         <!-- Main Content (Left Column) -->
@@ -393,7 +393,6 @@ const filteredCourses = computed(() => {
               >
                 ฟรี
               </h2>
-              <span class="status-pill status-success">ระยะเวลาจำกัด</span>
             </div>
 
             <NuxtLink

Frontend-Learner/pages/browse/opencovery.vue

@@ -63,7 +63,7 @@ const course = {
     <div class="container mx-auto max-w-6xl px-6">
       
       <!-- Back Button -->
-      <NuxtLink to="/browse/discovery" class="inline-flex items-center gap-2 text-slate-400 hover:text-white mb-8 transition-colors">
+      <NuxtLink to="/browse" class="inline-flex items-center gap-2 text-slate-400 hover:text-white mb-8 transition-colors">
         <svg xmlns="http://www.w3.org/2000/svg" class="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor">
           <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M10 19l-7-7m0 0l7-7m-7 7h18" />
         </svg>
@@ -126,11 +126,6 @@ const course = {
             <div class="mb-8 text-center lg:text-left">
               <span class="text-lg text-slate-500 line-through mr-4">{{ course.originalPrice }}</span>
               <span class="text-5xl font-black text-white tracking-tight">{{ course.price }}</span>
-              <div class="mt-4">
-                 <span class="inline-block px-3 py-1 rounded-lg bg-emerald-500/10 text-emerald-400 text-xs font-bold border border-emerald-500/20 uppercase tracking-wider">
-                   ระยะเวลาจำกัด
-                 </span>
-              </div>
             </div>
 
             <NuxtLink to="/auth/register" class="flex items-center justify-center w-full py-4 bg-blue-600 hover:bg-blue-500 text-white rounded-xl font-bold text-lg shadow-lg shadow-blue-600/30 transition-all hover:-translate-y-1 mb-6">