refactor: add an understanding of nullable for swagger gen

ApiDto/Responses/CampusBasicInfoResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents basic information about a campus.
@@ -8,11 +10,13 @@ public class CampusBasicInfoResponse
     /// <summary>
     /// Gets or sets the unique identifier of the campus.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the code name of the campus.
     /// </summary>
+    [Required]
     public required string CodeName { get; set; }
 
     /// <summary>

ApiDto/Responses/CampusDetailsResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents detailed information about a campus.
@@ -8,11 +10,13 @@ public class CampusDetailsResponse
     /// <summary>
     /// Gets or sets the unique identifier of the campus.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the code name of the campus.
     /// </summary>
+    [Required]
     public required string CodeName { get; set; }
 
     /// <summary>

ApiDto/Responses/DisciplineResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents information about a discipline.
@@ -8,10 +10,12 @@ public class DisciplineResponse
     /// <summary>
     /// Gets or sets the unique identifier of the discipline.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the discipline.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 }

ApiDto/Responses/ErrorResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// A class for providing information about an error
@@ -9,10 +11,12 @@ public class ErrorResponse
     /// The text or translation code of the error. This field may not contain information in specific scenarios.
     /// For example, it might be empty for HTTP 204 responses where no content is returned or if the validation texts have not been configured.
     /// </summary>
+    [Required]
     public required string Error { get; set; }
     /// <summary>
     /// In addition to returning the response code in the header, it is also duplicated in this field.
     /// Represents the HTTP response code.
     /// </summary>
+    [Required]
     public required int Code { get; set; }
 }

ApiDto/Responses/FacultyDetailsResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents detailed information about a faculty.
@@ -8,11 +10,13 @@ public class FacultyDetailsResponse
     /// <summary>
     /// Gets or sets the unique identifier of the faculty.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the faculty.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 
     /// <summary>

ApiDto/Responses/FacultyResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents basic information about a faculty.
@@ -8,11 +10,13 @@ public class FacultyResponse
     /// <summary>
     /// Gets or sets the unique identifier of the faculty.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the faculty.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 
     /// <summary>

ApiDto/Responses/GroupDetailsResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents detailed information about a group.
@@ -8,16 +10,19 @@ public class GroupDetailsResponse
     /// <summary>
     /// Gets or sets the unique identifier of the group.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the group.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets the course number of the group.
     /// </summary>
+    [Required]
     public int CourseNumber { get; set; }
 
     /// <summary>

ApiDto/Responses/GroupResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents basic information about a group.
@@ -8,16 +10,19 @@ public class GroupResponse
     /// <summary>
     /// Gets or sets the unique identifier of the group.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the group.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets the course number of the group.
     /// </summary>
+    [Required]
     public int CourseNumber { get; set; }
 
     /// <summary>

ApiDto/Responses/ProfessorResponse.cs

@@ -1,4 +1,6 @@
-namespace Mirea.Api.Dto.Responses;
+using System.ComponentModel.DataAnnotations;
+
+namespace Mirea.Api.Dto.Responses;
 
 /// <summary>
 /// Represents information about a professor.
@@ -8,11 +10,13 @@ public class ProfessorResponse
     /// <summary>
     /// Gets or sets the unique identifier of the professor.
     /// </summary>
+    [Required]
     public int Id { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the professor.
     /// </summary>
+    [Required]
     public required string Name { get; set; }
 
     /// <summary>