feat(album): add cover picture functionality to albums and enhance album management API

Models/DataBase/Album.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Foxel.Models.DataBase;
 
@@ -14,5 +15,9 @@ public class Album : BaseModel
     [Required]
     public User User { get; set; }
 
+    public int? CoverPictureId { get; set; }
+    [ForeignKey("CoverPictureId")]
+    public Picture? CoverPicture { get; set; }
+
     public ICollection<Picture>? Pictures { get; set; }
 }

Models/Request/Album/AlbumCreateRequest.cs

@@ -0,0 +1,16 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Foxel.Models.Request.Album
+{
+    public class AlbumCreateRequest
+    {
+        [Required(ErrorMessage = "相册名称不能为空")]
+        [StringLength(100, ErrorMessage = "相册名称长度不能超过100个字符")]
+        public string Name { get; set; } = string.Empty;
+
+        [StringLength(500, ErrorMessage = "相册描述长度不能超过500个字符")]
+        public string? Description { get; set; }
+
+        public int? CoverPictureId { get; set; }
+    }
+}

Models/Request/Album/AlbumUpdateRequest.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Foxel.Models.Request.Album
+{
+    public class AlbumUpdateRequest
+    {
+        [StringLength(100, ErrorMessage = "相册名称长度不能超过100个字符")]
+        public string? Name { get; set; }
+
+        [StringLength(500, ErrorMessage = "相册描述长度不能超过500个字符")]
+        public string? Description { get; set; }
+
+        public int? CoverPictureId { get; set; }
+    }
+}

Models/Request/Album/CreateAlbumRequest.cs

@@ -10,4 +10,7 @@ public record CreateAlbumRequest
     
     [StringLength(500)]
     public string? Description { get; set; }
+    
+    
+    public int? CoverPictureId { get; set; }
 }

Models/Response/Album/AlbumResponse.cs

@@ -7,9 +7,11 @@ public record AlbumResponse
     public int Id { get; set; }
     public string Name { get; set; } = string.Empty;
     public string Description { get; set; } = string.Empty;
-    public int PictureCount { get; set; } = 0;
     public int UserId { get; set; }
     public string? Username { get; set; }
     public DateTime CreatedAt { get; set; }
     public DateTime UpdatedAt { get; set; }
+    public string? CoverPicturePath { get; set; }
+    public string? CoverPictureThumbnailPath { get; set; }
+    public int PictureCount { get; set; }
 }