add xmldoc comments

web/backend/Service/Service.Auth/RegisterService.cs

@@ -9,6 +9,14 @@ using Service.Emails;
 
 namespace Service.Auth;
 
+/// <summary>
+/// Handles registration of new user accounts, including uniqueness validation, password hashing,
+/// token issuance, and sending the registration confirmation email.
+/// </summary>
+/// <param name="authRepo">Repository used to check for existing users and persist the new account.</param>
+/// <param name="passwordInfrastructure">Infrastructure component used to hash the user's plain-text password.</param>
+/// <param name="tokenService">Service used to generate access, refresh, and confirmation tokens.</param>
+/// <param name="emailService">Service used to send the registration confirmation email.</param>
 public class RegisterService(
     IAuthRepository authRepo,
     IPasswordInfrastructure passwordInfrastructure,
@@ -16,6 +24,13 @@ public class RegisterService(
     IEmailService emailService
 ) : IRegisterService
 {
+    /// <summary>
+    /// Verifies that no existing user account has the same username or email as the given account.
+    /// </summary>
+    /// <param name="userAccount">The candidate user account whose username and email should be checked for uniqueness.</param>
+    /// <exception cref="Domain.Exceptions.ConflictException">
+    /// Thrown when an existing account already has the same username or email address.
+    /// </exception>
     private async Task ValidateUserDoesNotExist(UserAccount userAccount)
     {
         // Check if user already exists
@@ -32,6 +47,21 @@ public class RegisterService(
         }
     }
 
+    /// <summary>
+    /// Registers a new user account: validates uniqueness, hashes the password, persists the account,
+    /// issues access/refresh/confirmation tokens, and attempts to send the registration confirmation email.
+    /// </summary>
+    /// <param name="userAccount">The user account details to register.</param>
+    /// <param name="password">The plain-text password to hash and store for the new account.</param>
+    /// <returns>
+    /// A <see cref="RegisterServiceReturn"/> describing the outcome. If token generation fails, the
+    /// returned value has <see cref="RegisterServiceReturn.IsAuthenticated"/> set to <c>false</c> and no tokens.
+    /// Otherwise tokens are populated and <see cref="RegisterServiceReturn.EmailSent"/> reflects whether the
+    /// confirmation email was sent successfully (failures to send the email are swallowed and do not fail registration).
+    /// </returns>
+    /// <exception cref="Domain.Exceptions.ConflictException">
+    /// Thrown when an existing account already has the same username or email address.
+    /// </exception>
     public async Task<RegisterServiceReturn> RegisterAsync(
         UserAccount userAccount,
         string password