adding favorite feature

src/application/dtos/favorites_dto.rs

@@ -0,0 +1,21 @@
+use serde::{Deserialize, Serialize};
+use chrono::{DateTime, Utc};
+
+/// DTO for favorites item
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct FavoriteItemDto {
+    /// Unique identifier for the favorite entry
+    pub id: String,
+    
+    /// User ID who owns this favorite
+    pub user_id: String,
+    
+    /// ID of the favorited item (file or folder)
+    pub item_id: String,
+    
+    /// Type of the item ('file' or 'folder')
+    pub item_type: String,
+    
+    /// When the item was added to favorites
+    pub created_at: DateTime<Utc>,
+}

src/application/dtos/mod.rs

@@ -6,4 +6,5 @@ pub mod user_dto;
 pub mod trash_dto;
 pub mod search_dto;
 pub mod share_dto;
+pub mod favorites_dto;