Replace shared email commands with MediatR notifications (#280)

docs/web/architecture.md

@@ -77,7 +77,7 @@ flowchart TB
     subgraph SHARED["Shared Projects"]
         direction LR
         SH1["Shared.Contracts<br/>ResponseBody envelope"]
-        SH2["Shared.Application<br/>ValidationBehavior,<br/>cross-slice email commands"]
+        SH2["Shared.Application<br/>ValidationBehavior"]
     end
 
     subgraph DOMAIN["Domain Layer"]
@@ -98,7 +98,7 @@ flowchart TB
     DB[("Database (SQL Server)")]
 
     HOST -- "discovers controllers via<br/>AddApplicationPart" --> SLICES
-    S1 -- "SendRegistrationEmailCommand<br/>(via Shared.Application contract)" --> S3
+    S3 == "ProjectReference<br/>(handles UserRegisteredNotification & ConfirmationEmailResendRequestedNotification)" ==> S1
     S1 -- "ProjectReference<br/>(avatar upload)" --> S5
 
     SLICES --> SHARED
@@ -172,8 +172,10 @@ brewery photo upload command) rather than bound to an HTTP route directly.
   `Infrastructure.Email.Templates` for Emails, `Infrastructure.FileUpload` for
   PhotoUpload)
 - `Shared.Contracts`, `Shared.Application`
-- No other `Features.*` project, with one exception: `Features.Users` references
-  `Features.PhotoUpload` directly for avatar uploads
+- No other `Features.*` project, with two exceptions: `Features.Users`
+  references `Features.PhotoUpload` directly for avatar uploads, and
+  `Features.Emails` references `Features.Users` directly to handle
+  `UserRegisteredNotification` and `ConfirmationEmailResendRequestedNotification`
 
 **Rules**:
 
@@ -191,7 +193,7 @@ needs it, or because duplicating it four times would be worse than sharing it
 | Project              | Purpose                                                                                                                                                                                                                                 |
 | -------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `Shared.Contracts`   | `ResponseBody<T>`/`ResponseBody`, the API response envelope every controller returns                                                                                                                                                    |
-| `Shared.Application` | `ValidationBehavior<TRequest,TResponse>` (the MediatR pipeline behavior that runs FluentValidation before a handler executes) and the cross-slice email commands (`SendRegistrationEmailCommand`, `SendResendConfirmationEmailCommand`) |
+| `Shared.Application` | `ValidationBehavior<TRequest,TResponse>`, the MediatR pipeline behavior that runs FluentValidation before a handler executes |
 
 **Rules**:
 

docs/web/diagrams/auth/registration.mmd

@@ -127,9 +127,9 @@ sequenceDiagram
             TokenSvc-->>RegHandler: Confirmation Token
             deactivate TokenSvc
 
-            RegHandler->>Mediator: Send(SendRegistrationEmailCommand) (Shared.Application cross-slice contract)
+            RegHandler->>Mediator: Publish(UserRegisteredNotification)
             activate Mediator
-            Note right of Mediator: Routed to Features.Emails' SendRegistrationEmailHandler — the second of two cross-slice dispatches in this flow (profile creation is the first)
+            Note right of Mediator: Features.Emails has a direct ProjectReference on Features.Users and handles the notification via UserRegisteredNotificationHandler — the second of two cross-slice dispatches in this flow (profile creation is the first)
             Mediator->>EmailDispatcher: SendRegistrationEmailAsync(firstName, email, confirmationToken)
             activate EmailDispatcher
 
@@ -147,15 +147,15 @@ sequenceDiagram
             SMTP-->>EmailDispatcher: Success / throws
             deactivate SMTP
             deactivate EmailDispatcher
-            deactivate Mediator
 
             alt Email sent successfully
-                RegHandler->>RegHandler: emailSent = true
-            else mediator.Send throws
-                RegHandler->>RegHandler: catch(Exception), log to stderr, emailSent = false
+                Note right of Mediator: UserRegisteredNotificationHandler completes normally
+            else EmailDispatcher throws
+                Note right of Mediator: UserRegisteredNotificationHandler catches and logs the exception — registration is unaffected
             end
+            deactivate Mediator
 
-            RegHandler-->>Mediator: RegistrationPayload(userAccountId, username, refreshToken, accessToken, confirmationEmailSent)
+            RegHandler-->>Mediator: RegistrationPayload(userAccountId, username, refreshToken, accessToken)
             deactivate RegHandler
             Mediator-->>API: RegistrationPayload
             deactivate Mediator

docs/web/diagrams/auth/resend-confirmation.mmd

@@ -51,13 +51,20 @@ sequenceDiagram
             TokenSvc-->>ResendHandler: confirmation token
             deactivate TokenSvc
 
-            ResendHandler->>Mediator: Send(SendResendConfirmationEmailCommand)
+            ResendHandler->>Mediator: Publish(ConfirmationEmailResendRequestedNotification)
             activate Mediator
+            Note right of Mediator: Features.Emails has a direct ProjectReference on Features.Users and handles the notification via ConfirmationEmailResendRequestedNotificationHandler
             Mediator->>EmailDispatcher: SendResendConfirmationEmailAsync(firstName, email, confirmationToken)
             activate EmailDispatcher
             EmailDispatcher->>Template: Render email (same Razor pipeline as registration)
             EmailDispatcher->>SMTP: SendAsync(email, subject, body)
             deactivate EmailDispatcher
+
+            alt Email sent successfully
+                Note right of Mediator: ConfirmationEmailResendRequestedNotificationHandler completes normally
+            else EmailDispatcher throws
+                Note right of Mediator: ConfirmationEmailResendRequestedNotificationHandler catches and logs the exception — the resend request is unaffected
+            end
             deactivate Mediator
         end
     end

docs/web/diagrams/vertical-slice.md

@@ -16,13 +16,14 @@ doesn't wire up any slice; it applies schema directly.
 
 ## Project reference dependencies
 
-Solid arrows are compile-time project references. Dashed arrows are the two
-places slices talk to each other without a direct reference: the email MediatR
-contract routed through `Shared.Application`, and the one place that pattern is
-broken outright. Every DB-backed slice depends on the same three foundation
-projects (`Shared.Contracts`, `Domain.Entities`, `Database.Connection`) — drawn
-as one box instead of fifteen separate arrows; see the notes for what else each
-of those foundation projects pulls in.
+Solid arrows are compile-time project references — every slice-to-slice
+dependency is one now that the email MediatR contract has moved off
+`Shared.Application`: `Features.Users` on `Features.PhotoUpload` for avatar
+uploads, and `Features.Emails` on `Features.Users` for the registration and
+resend-confirmation notifications. Every DB-backed slice depends on the same
+three foundation projects (`Shared.Contracts`, `Domain.Entities`,
+`Database.Connection`) — drawn as one box instead of fifteen separate arrows;
+see the notes for what else each of those foundation projects pulls in.
 
 ```mermaid
 --8<-- "web/diagrams/vertical-slice/project-references.mmd"
@@ -54,17 +55,20 @@ of those foundation projects pulls in.
   - `Features.Beers` is scaffolded (project + references only, no source files
     yet)
 
-- **The one exception to slice isolation**: `Features.Users` takes a direct
-  project reference to `Features.PhotoUpload`
-  - sends its `UploadPhotoCommand` via MediatR from `UploadAvatarHandler`
-  - unlike the email flow, the command type lives in the target slice itself,
-    not in `Shared.Application`
+- **The exceptions to slice isolation**:
+  - `Features.Users` takes a direct project reference to `Features.PhotoUpload`
+    - sends its `UploadPhotoCommand` via MediatR from `UploadAvatarHandler`
+    - the command type lives in the target slice itself, not in
+      `Shared.Application`
+  - `Features.Emails` takes a direct project reference to `Features.Users`
+    - handles `UserRegisteredNotification` (published from
+      `RegisterUserHandler`) and `ConfirmationEmailResendRequestedNotification`
+      (published from `ResendConfirmationEmailHandler`)
+    - both notification types live in `Features.Users`
+      (`Features.Auth.Notifications`), not in `Shared.Application`
 
 - **Shared.Application**:
   - `ValidationBehavior` (MediatR pipeline)
-  - Cross-slice email commands (`SendRegistrationEmailCommand`,
-    `SendResendConfirmationEmailCommand`)
-  - MediatR command contract (not project reference)
   - Every slice (including `Features.Emails`) references it for the pipeline
     behavior alone
 

docs/web/diagrams/vertical-slice/project-references.mmd

@@ -31,8 +31,7 @@ EmailTemplates["Infrastructure.Email.Templates"]
 end
 
 UsersSlice == project ref, sends UploadPhotoCommand ==> PhotoSlice
-UsersSlice -. sends email commands .-> SharedApp["Shared.Application<br>(email command contract)"]
-EmailsSlice -. handles email commands .-> SharedApp
+EmailsSlice == project ref, handles UserRegisteredNotification & ConfirmationEmailResendRequestedNotification ==> UsersSlice
 BrewerySlice --> FOUNDATION
 LocationsSlice --> FOUNDATION
 BeersSlice --> FOUNDATION

web/backend/Features/Features.Emails.Tests/Commands/SendRegistrationEmailHandlerTests.cs

@@ -1,24 +0,0 @@
-using Features.Emails.Commands.SendRegistrationEmail;
-using Features.Emails.Services;
-using Moq;
-using Shared.Application.Emails;
-
-namespace Features.Emails.Tests.Commands;
-
-public class SendRegistrationEmailHandlerTests
-{
-    [Fact]
-    public async Task Handle_DelegatesToEmailDispatcher()
-    {
-        Mock<IEmailDispatcher> dispatcherMock = new();
-        SendRegistrationEmailHandler handler = new(dispatcherMock.Object);
-        SendRegistrationEmailCommand command = new("Aaron", "aaron@example.com", "token-123");
-
-        await handler.Handle(command, CancellationToken.None);
-
-        dispatcherMock.Verify(
-            d => d.SendRegistrationEmailAsync("Aaron", "aaron@example.com", "token-123"),
-            Times.Once
-        );
-    }
-}

web/backend/Features/Features.Emails.Tests/Commands/SendResendConfirmationEmailHandlerTests.cs

@@ -1,24 +0,0 @@
-using Features.Emails.Commands.SendResendConfirmationEmail;
-using Features.Emails.Services;
-using Moq;
-using Shared.Application.Emails;
-
-namespace Features.Emails.Tests.Commands;
-
-public class SendResendConfirmationEmailHandlerTests
-{
-    [Fact]
-    public async Task Handle_DelegatesToEmailDispatcher()
-    {
-        Mock<IEmailDispatcher> dispatcherMock = new();
-        SendResendConfirmationEmailHandler handler = new(dispatcherMock.Object);
-        SendResendConfirmationEmailCommand command = new("Aaron", "aaron@example.com", "token-456");
-
-        await handler.Handle(command, CancellationToken.None);
-
-        dispatcherMock.Verify(
-            d => d.SendResendConfirmationEmailAsync("Aaron", "aaron@example.com", "token-456"),
-            Times.Once
-        );
-    }
-}

web/backend/Features/Features.Emails.Tests/Notifications/ConfirmationEmailResendRequestedNotificationHandlerTests.cs

@@ -0,0 +1,63 @@
+using Features.Auth.Notifications;
+using Features.Emails.Notifications;
+using Features.Emails.Services;
+using FluentAssertions;
+using Microsoft.Extensions.Logging;
+using Moq;
+
+namespace Features.Emails.Tests.Notifications;
+
+public class ConfirmationEmailResendRequestedNotificationHandlerTests
+{
+    [Fact]
+    public async Task Handle_DelegatesToEmailDispatcher()
+    {
+        Mock<IEmailDispatcher> dispatcherMock = new();
+        ConfirmationEmailResendRequestedNotificationHandler handler = new(
+            dispatcherMock.Object,
+            Mock.Of<ILogger<ConfirmationEmailResendRequestedNotificationHandler>>()
+        );
+        ConfirmationEmailResendRequestedNotification notification = new(
+            Guid.NewGuid(),
+            "Aaron",
+            "aaron@example.com",
+            "token-456"
+        );
+
+        await handler.Handle(notification, CancellationToken.None);
+
+        dispatcherMock.Verify(
+            d => d.SendResendConfirmationEmailAsync("Aaron", "aaron@example.com", "token-456"),
+            Times.Once
+        );
+    }
+
+    [Fact]
+    public async Task Handle_SwallowsDispatcherFailure()
+    {
+        Mock<IEmailDispatcher> dispatcherMock = new();
+        dispatcherMock
+            .Setup(d =>
+                d.SendResendConfirmationEmailAsync(
+                    It.IsAny<string>(),
+                    It.IsAny<string>(),
+                    It.IsAny<string>()
+                )
+            )
+            .ThrowsAsync(new Exception("smtp down"));
+        ConfirmationEmailResendRequestedNotificationHandler handler = new(
+            dispatcherMock.Object,
+            Mock.Of<ILogger<ConfirmationEmailResendRequestedNotificationHandler>>()
+        );
+        ConfirmationEmailResendRequestedNotification notification = new(
+            Guid.NewGuid(),
+            "Aaron",
+            "aaron@example.com",
+            "token-456"
+        );
+
+        Func<Task> act = async () => await handler.Handle(notification, CancellationToken.None);
+
+        await act.Should().NotThrowAsync();
+    }
+}

web/backend/Features/Features.Emails.Tests/Notifications/UserRegisteredNotificationHandlerTests.cs

@@ -0,0 +1,63 @@
+using Features.Auth.Notifications;
+using Features.Emails.Notifications;
+using Features.Emails.Services;
+using FluentAssertions;
+using Microsoft.Extensions.Logging;
+using Moq;
+
+namespace Features.Emails.Tests.Notifications;
+
+public class UserRegisteredNotificationHandlerTests
+{
+    [Fact]
+    public async Task Handle_DelegatesToEmailDispatcher()
+    {
+        Mock<IEmailDispatcher> dispatcherMock = new();
+        UserRegisteredNotificationHandler handler = new(
+            dispatcherMock.Object,
+            Mock.Of<ILogger<UserRegisteredNotificationHandler>>()
+        );
+        UserRegisteredNotification notification = new(
+            Guid.NewGuid(),
+            "Aaron",
+            "aaron@example.com",
+            "token-123"
+        );
+
+        await handler.Handle(notification, CancellationToken.None);
+
+        dispatcherMock.Verify(
+            d => d.SendRegistrationEmailAsync("Aaron", "aaron@example.com", "token-123"),
+            Times.Once
+        );
+    }
+
+    [Fact]
+    public async Task Handle_SwallowsDispatcherFailure()
+    {
+        Mock<IEmailDispatcher> dispatcherMock = new();
+        dispatcherMock
+            .Setup(d =>
+                d.SendRegistrationEmailAsync(
+                    It.IsAny<string>(),
+                    It.IsAny<string>(),
+                    It.IsAny<string>()
+                )
+            )
+            .ThrowsAsync(new Exception("smtp down"));
+        UserRegisteredNotificationHandler handler = new(
+            dispatcherMock.Object,
+            Mock.Of<ILogger<UserRegisteredNotificationHandler>>()
+        );
+        UserRegisteredNotification notification = new(
+            Guid.NewGuid(),
+            "Aaron",
+            "aaron@example.com",
+            "token-123"
+        );
+
+        Func<Task> act = async () => await handler.Handle(notification, CancellationToken.None);
+
+        await act.Should().NotThrowAsync();
+    }
+}

web/backend/Features/Features.Emails/Commands/SendRegistrationEmail/SendRegistrationEmailHandler.cs

@@ -1,22 +0,0 @@
-using Features.Emails.Services;
-using MediatR;
-using Shared.Application.Emails;
-
-namespace Features.Emails.Commands.SendRegistrationEmail;
-
-/// <summary>
-///     Handles <see cref="SendRegistrationEmailCommand" />, the cross-slice command sent by Features.Users
-///     after a new user registers.
-/// </summary>
-public class SendRegistrationEmailHandler(IEmailDispatcher emailDispatcher)
-    : IRequestHandler<SendRegistrationEmailCommand>
-{
-    public Task Handle(SendRegistrationEmailCommand request, CancellationToken cancellationToken)
-    {
-        return emailDispatcher.SendRegistrationEmailAsync(
-            request.FirstName,
-            request.Email,
-            request.ConfirmationToken
-        );
-    }
-}

web/backend/Features/Features.Emails/Commands/SendResendConfirmationEmail/SendResendConfirmationEmailHandler.cs

@@ -1,25 +0,0 @@
-using Features.Emails.Services;
-using MediatR;
-using Shared.Application.Emails;
-
-namespace Features.Emails.Commands.SendResendConfirmationEmail;
-
-/// <summary>
-///     Handles <see cref="SendResendConfirmationEmailCommand" />, the cross-slice command sent by Features.Users
-///     when a user requests a fresh confirmation link.
-/// </summary>
-public class SendResendConfirmationEmailHandler(IEmailDispatcher emailDispatcher)
-    : IRequestHandler<SendResendConfirmationEmailCommand>
-{
-    public Task Handle(
-        SendResendConfirmationEmailCommand request,
-        CancellationToken cancellationToken
-    )
-    {
-        return emailDispatcher.SendResendConfirmationEmailAsync(
-            request.FirstName,
-            request.Email,
-            request.ConfirmationToken
-        );
-    }
-}

web/backend/Features/Features.Emails/Features.Emails.csproj

@@ -18,5 +18,6 @@
         <ProjectReference Include="..\..\Infrastructure\Infrastructure.Email\Infrastructure.Email.csproj" />
         <ProjectReference Include="..\..\Infrastructure\Infrastructure.Email.Templates\Infrastructure.Email.Templates.csproj" />
         <ProjectReference Include="..\..\Shared\Shared.Application\Shared.Application.csproj" />
+        <ProjectReference Include="..\Features.Users\Features.Users.csproj" />
     </ItemGroup>
 </Project>

web/backend/Features/Features.Emails/Notifications/ConfirmationEmailResendRequestedNotificationHandler.cs

@@ -0,0 +1,44 @@
+using Features.Auth.Notifications;
+using Features.Emails.Services;
+using MediatR;
+using Microsoft.Extensions.Logging;
+
+namespace Features.Emails.Notifications;
+
+/// <summary>
+///     Handles <see cref="ConfirmationEmailResendRequestedNotification" />, the cross-slice notification
+///     published by Features.Users when a user requests a fresh confirmation link, by sending the resend
+///     confirmation email.
+/// </summary>
+public class ConfirmationEmailResendRequestedNotificationHandler(
+    IEmailDispatcher emailDispatcher,
+    ILogger<ConfirmationEmailResendRequestedNotificationHandler> logger
+) : INotificationHandler<ConfirmationEmailResendRequestedNotification>
+{
+    /// <remarks>
+    ///     Delivery failures are logged and swallowed rather than rethrown, so that a broken mail server
+    ///     never fails the resend request that already succeeded.
+    /// </remarks>
+    public async Task Handle(
+        ConfirmationEmailResendRequestedNotification notification,
+        CancellationToken cancellationToken
+    )
+    {
+        try
+        {
+            await emailDispatcher.SendResendConfirmationEmailAsync(
+                notification.FirstName,
+                notification.Email,
+                notification.ConfirmationToken
+            );
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(
+                ex,
+                "Failed to send resend confirmation email to user {UserId}",
+                notification.UserId
+            );
+        }
+    }
+}

web/backend/Features/Features.Emails/Notifications/UserRegisteredNotificationHandler.cs

@@ -0,0 +1,40 @@
+using Features.Auth.Notifications;
+using Features.Emails.Services;
+using MediatR;
+using Microsoft.Extensions.Logging;
+
+namespace Features.Emails.Notifications;
+
+/// <summary>
+///     Handles <see cref="UserRegisteredNotification" />, the cross-slice notification published by
+///     Features.Users after a new user registers, by sending the registration confirmation email.
+/// </summary>
+public class UserRegisteredNotificationHandler(
+    IEmailDispatcher emailDispatcher,
+    ILogger<UserRegisteredNotificationHandler> logger
+) : INotificationHandler<UserRegisteredNotification>
+{
+    /// <remarks>
+    ///     Delivery failures are logged and swallowed rather than rethrown, so that a broken mail server
+    ///     never fails the registration that already succeeded.
+    /// </remarks>
+    public async Task Handle(UserRegisteredNotification notification, CancellationToken cancellationToken)
+    {
+        try
+        {
+            await emailDispatcher.SendRegistrationEmailAsync(
+                notification.FirstName,
+                notification.Email,
+                notification.ConfirmationToken
+            );
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(
+                ex,
+                "Failed to send registration confirmation email to user {UserId}",
+                notification.UserId
+            );
+        }
+    }
+}

web/backend/Features/Features.Users.Tests/Commands/RegisterUserHandlerTests.cs

@@ -2,13 +2,13 @@ using Domain.Exceptions;
 using Features.Auth.Commands.Authentication.RegisterUser;
 using Features.Auth.Dtos;
 using Features.Auth.Identity;
+using Features.Auth.Notifications;
 using Features.Auth.Services;
 using Features.Auth.Tests.TestSupport;
 using FluentAssertions;
 using MediatR;
 using Microsoft.AspNetCore.Identity;
 using Moq;
-using Shared.Application.Emails;
 
 namespace Features.Auth.Tests.Commands;
 
@@ -86,10 +86,18 @@ public class RegisterUserHandlerTests
         result.Username.Should().Be(command.Username);
         result.AccessToken.Should().Be("access-token");
         result.RefreshToken.Should().Be("refresh-token");
-        result.ConfirmationEmailSent.Should().BeTrue();
 
         _mediatorMock.Verify(
-            x => x.Send(It.IsAny<SendRegistrationEmailCommand>(), It.IsAny<CancellationToken>()),
+            x =>
+                x.Publish(
+                    It.Is<UserRegisteredNotification>(n =>
+                        n.UserId == expectedUserId
+                        && n.FirstName == command.FirstName
+                        && n.Email == command.Email
+                        && n.ConfirmationToken == "confirmation-token"
+                    ),
+                    It.IsAny<CancellationToken>()
+                ),
             Times.Once
         );
     }
@@ -177,31 +185,4 @@ public class RegisterUserHandlerTests
         );
     }
 
-    [Fact]
-    public async Task Handle_SwallowsEmailFailure_AndReportsEmailNotSent()
-    {
-        RegisterUserCommand command = ValidCommand();
-
-        _userManagerMock
-            .Setup(x => x.CreateAsync(It.IsAny<ApplicationUser>(), command.Password))
-            .Callback<ApplicationUser, string>((u, _) => u.Id = Guid.NewGuid())
-            .ReturnsAsync(IdentityResult.Success);
-
-        _tokenServiceMock
-            .Setup(x => x.GenerateAccessToken(It.IsAny<Guid>(), It.IsAny<string>()))
-            .Returns("access-token");
-        _tokenServiceMock
-            .Setup(x => x.GenerateRefreshToken(It.IsAny<Guid>(), It.IsAny<string>()))
-            .Returns("refresh-token");
-        _mediatorMock
-            .Setup(x =>
-                x.Send(It.IsAny<SendRegistrationEmailCommand>(), It.IsAny<CancellationToken>())
-            )
-            .ThrowsAsync(new Exception("smtp down"));
-
-        RegistrationPayload result = await _handler.Handle(command, CancellationToken.None);
-
-        result.ConfirmationEmailSent.Should().BeFalse();
-        result.AccessToken.Should().Be("access-token");
-    }
 }

web/backend/Features/Features.Users.Tests/Commands/ResendConfirmationEmailHandlerTests.cs

@@ -1,11 +1,11 @@
 using Features.Auth.Commands.Authentication.ResendConfirmationEmail;
 using Features.Auth.Identity;
+using Features.Auth.Notifications;
 using Features.Auth.Services;
 using Features.Auth.Tests.TestSupport;
 using MediatR;
 using Microsoft.AspNetCore.Identity;
 using Moq;
-using Shared.Application.Emails;
 
 namespace Features.Auth.Tests.Commands;
 
@@ -47,11 +47,12 @@ public class ResendConfirmationEmailHandlerTests
 
         _mediatorMock.Verify(
             x =>
-                x.Send(
-                    It.Is<SendResendConfirmationEmailCommand>(c =>
-                        c.FirstName == "Aaron"
-                        && c.Email == "aaron@example.com"
-                        && c.ConfirmationToken == "fresh-token"
+                x.Publish(
+                    It.Is<ConfirmationEmailResendRequestedNotification>(n =>
+                        n.UserId == userId
+                        && n.FirstName == "Aaron"
+                        && n.Email == "aaron@example.com"
+                        && n.ConfirmationToken == "fresh-token"
                     ),
                     It.IsAny<CancellationToken>()
                 ),
@@ -71,8 +72,8 @@ public class ResendConfirmationEmailHandlerTests
 
         _mediatorMock.Verify(
             x =>
-                x.Send(
-                    It.IsAny<SendResendConfirmationEmailCommand>(),
+                x.Publish(
+                    It.IsAny<ConfirmationEmailResendRequestedNotification>(),
                     It.IsAny<CancellationToken>()
                 ),
             Times.Never
@@ -92,8 +93,8 @@ public class ResendConfirmationEmailHandlerTests
 
         _mediatorMock.Verify(
             x =>
-                x.Send(
-                    It.IsAny<SendResendConfirmationEmailCommand>(),
+                x.Publish(
+                    It.IsAny<ConfirmationEmailResendRequestedNotification>(),
                     It.IsAny<CancellationToken>()
                 ),
             Times.Never

web/backend/Features/Features.Users/Commands/Authentication/RegisterUser/RegisterUserHandler.cs

@@ -3,17 +3,17 @@ using Domain.Exceptions;
 using Features.Auth.Commands.Profile.CreateUserProfile;
 using Features.Auth.Dtos;
 using Features.Auth.Identity;
+using Features.Auth.Notifications;
 using Features.Auth.Services;
 using MediatR;
 using Microsoft.AspNetCore.Identity;
-using Shared.Application.Emails;
 
 namespace Features.Auth.Commands.Authentication.RegisterUser;
 
 /// <summary>
 ///     Handles <see cref="RegisterUserCommand" />: creates the user via <see cref="UserManager{TUser}" />
 ///     (which validates uniqueness and hashes the password), issues access/refresh/confirmation tokens, and
-///     attempts to send the registration confirmation email via Features.Emails.
+///     publishes <see cref="UserRegisteredNotification" /> for Features.Emails to send the confirmation email.
 /// </summary>
 public class RegisterUserHandler(
     UserManager<ApplicationUser> userManager,
@@ -60,31 +60,19 @@ public class RegisterUserHandler(
                 user.Id,
                 user.UserName,
                 string.Empty,
-                string.Empty,
-                false
+                string.Empty
             );
 
-        bool emailSent = false;
-        try
-        {
-            await mediator.Send(
-                new SendRegistrationEmailCommand(user.FirstName, user.Email, confirmationToken),
-                cancellationToken
-            );
-            emailSent = true;
-        }
-        catch (Exception ex)
-        {
-            await Console.Error.WriteLineAsync(ex.Message);
-            Console.WriteLine("Could not send email.");
-        }
+        await mediator.Publish(
+            new UserRegisteredNotification(user.Id, request.FirstName, user.Email, confirmationToken),
+            cancellationToken
+        );
 
         return new RegistrationPayload(
             user.Id,
             user.UserName,
             refreshToken,
-            accessToken,
-            emailSent
+            accessToken
         );
     }
 }

web/backend/Features/Features.Users/Commands/Authentication/ResendConfirmationEmail/ResendConfirmationEmailHandler.cs

@@ -1,14 +1,14 @@
 using Features.Auth.Identity;
+using Features.Auth.Notifications;
 using Features.Auth.Services;
 using MediatR;
 using Microsoft.AspNetCore.Identity;
-using Shared.Application.Emails;
 
 namespace Features.Auth.Commands.Authentication.ResendConfirmationEmail;
 
 /// <summary>
 ///     Handles <see cref="ResendConfirmationEmailCommand" /> by generating a fresh confirmation token and
-///     sending it via Features.Emails.
+///     publishing <see cref="ConfirmationEmailResendRequestedNotification" /> for Features.Emails to send it.
 /// </summary>
 /// <remarks>
 ///     Returns silently without sending an email if the user does not exist (to prevent user enumeration)
@@ -33,8 +33,13 @@ public class ResendConfirmationEmailHandler(
             return; // Already confirmed, no-op
 
         string confirmationToken = tokenService.GenerateConfirmationToken(user.Id, user.UserName);
-        await mediator.Send(
-            new SendResendConfirmationEmailCommand(user.FirstName, user.Email, confirmationToken),
+        await mediator.Publish(
+            new ConfirmationEmailResendRequestedNotification(
+                user.Id,
+                user.FirstName,
+                user.Email,
+                confirmationToken
+            ),
             cancellationToken
         );
     }

web/backend/Features/Features.Users/Dtos/AuthPayloads.cs

@@ -13,9 +13,7 @@ public record RegistrationPayload(
     Guid UserAccountId,
     string Username,
     string RefreshToken,
-    string AccessToken,
-    bool ConfirmationEmailSent
-);
+    string AccessToken);
 
 /// <summary>Payload returned to the client after a user account's email has been confirmed.</summary>
 public record ConfirmationPayload(Guid UserAccountId, DateTime ConfirmedDate);

web/backend/Features/Features.Users/Notifications/ConfirmationEmailResendRequestedNotification.cs

@@ -0,0 +1,14 @@
+using MediatR;
+
+namespace Features.Auth.Notifications;
+
+/// <summary>
+///     Published after a user requests a fresh confirmation link. Handled by Features.Emails to send the
+///     resend confirmation email.
+/// </summary>
+public record ConfirmationEmailResendRequestedNotification(
+    Guid UserId,
+    string FirstName,
+    string Email,
+    string ConfirmationToken
+) : INotification;

web/backend/Features/Features.Users/Notifications/UserRegisteredNotification.cs

@@ -0,0 +1,14 @@
+using MediatR;
+
+namespace Features.Auth.Notifications;
+
+/// <summary>
+///     Published after a new user registers. Handled by Features.Emails to send the registration
+///     confirmation email.
+/// </summary>
+public record UserRegisteredNotification(
+    Guid UserId,
+    string FirstName,
+    string Email,
+    string ConfirmationToken
+) : INotification;

web/backend/Shared/Shared.Application/Emails/SendRegistrationEmailCommand.cs

@@ -1,10 +0,0 @@
-using MediatR;
-
-namespace Shared.Application.Emails;
-
-/// <summary>
-///     Cross-slice command sent by Features.Users and handled by Features.Emails to dispatch a
-///     registration confirmation email, without either slice taking a project reference on the other.
-/// </summary>
-public record SendRegistrationEmailCommand(string FirstName, string Email, string ConfirmationToken)
-    : IRequest;

web/backend/Shared/Shared.Application/Emails/SendResendConfirmationEmailCommand.cs

@@ -1,13 +0,0 @@
-using MediatR;
-
-namespace Shared.Application.Emails;
-
-/// <summary>
-///     Cross-slice command sent by Features.Users and handled by Features.Emails to dispatch a
-///     fresh confirmation-link email, without either slice taking a project reference on the other.
-/// </summary>
-public record SendResendConfirmationEmailCommand(
-    string FirstName,
-    string Email,
-    string ConfirmationToken
-) : IRequest;

web/frontend/app/features/auth/auth.server.ts

@@ -21,9 +21,7 @@ interface LoginPayload {
     accessToken: string;
 }
 
-interface RegistrationPayload extends LoginPayload {
-    confirmationEmailSent: boolean;
-}
+type RegistrationPayload = LoginPayload;
 
 interface UpdateUsernamePayload {
     userAccountId: string;