fix(trash): add missing display fields to TrashedItemDto

Add category, icon_class, and icon_special_class fields to TrashedItemDto
to fix trash view rendering issues. The frontend expects these fields to
properly display file type information, icons, and deletion dates.

- category: Human-readable file category (e.g., "Image", "Document")
- icon_class: FontAwesome icon class for the file type
- icon_special_class: Special CSS class for icon styling

Fixes #107

src/application/dtos/trash_dto.rs

@@ -11,6 +11,12 @@ pub struct TrashedItemDto {
     pub original_path: String,
     pub trashed_at: DateTime<Utc>,
     pub days_until_deletion: i64,
+    /// Human-readable category (e.g., "Image", "Folder", "Document")
+    pub category: String,
+    /// FontAwesome icon class for the file type
+    pub icon_class: String,
+    /// Special CSS class for icon styling (e.g., "image-icon", "pdf-icon")
+    pub icon_special_class: String,
 }
 
 /// Request to move an item to trash