refactor: enhance admin dashboard and layout with blog management links

models/blog.js

@@ -91,7 +91,6 @@ const blogSchema = new mongoose.Schema({
 });
 
 // Indexes
-blogSchema.index({ slug: 1 });
 blogSchema.index({ status: 1, createdAt: -1 });
 blogSchema.index({ category: 1, status: 1 });
 blogSchema.index({ isFeatured: 1, status: 1 });

models/blogCategory.js

@@ -30,7 +30,6 @@ const blogCategorySchema = new mongoose.Schema({
 });
 
 // Indexes
-blogCategorySchema.index({ slug: 1 });
 blogCategorySchema.index({ isActive: 1, name: 1 });
 
 // Remove __v from JSON output

models/blogTag.js

@@ -26,7 +26,6 @@ const blogTagSchema = new mongoose.Schema({
 });
 
 // Indexes
-blogTagSchema.index({ slug: 1 });
 blogTagSchema.index({ isActive: 1, name: 1 });
 
 // Remove __v from JSON output

models/visa.js

@@ -179,9 +179,10 @@ const DetailedViewSchema = new mongoose.Schema(
 // Main VisaCountry Schema (Individual country object)
 const VisaCountrySchema = new mongoose.Schema(
   {
-    id: { type: Number, required: true, index: true },
-    name: { type: String, required: true, index: true },
-    slug: { type: String, required: true, unique: true, index: true },
+    // Không dùng `index: true` ở đây vì đã tạo index riêng cho hero.summaryList.* bên dưới
+    id: { type: Number, required: true },
+    name: { type: String, required: true },
+    slug: { type: String, required: true, unique: true },
     icon: { type: String, default: "" },
     services: {
       type: [String],