Get Collection

{
  "id": "uuid",
  "name": "Tokyo Street Recipes",
  "description": "My favorite street photography settings",
  "coverImageUrl": "https://...",
  "isPublic": true,
  "author": {
    "id": "uuid",
    "username": "johndoe",
    "avatarUrl": "https://..."
  },
  "items": [
    {
      "id": "uuid",
      "contentType": "recipe",
      "contentId": "uuid",
      "title": "Classic Chrome Street",
      "coverImageUrl": "https://...",
      "addedAt": "2024-01-15T10:30:00Z"
    }
  ],
  "itemCount": 12,
  "favoriteCount": 18,
  "isFavorited": false,
  "createdAt": "2024-01-15T10:30:00Z"
}