many fixes and improvements - rework for modules/ and common/

feat(emailer): add Postmark and Resend providers

backend/Modules/Creators/Features/CreateCreator.cs

@@ -0,0 +1,82 @@
+using Hutopy.Infrastructure.Security;
+using Hutopy.Modules.Creators.Data;
+
+namespace Hutopy.Modules.Creators.Features;
+
+[PublicAPI]
+public record CreateCreatorRequest(
+    Guid SlugReservationId,
+    Guid CreatorId);
+
+[PublicAPI]
+public sealed class CreateCreatorRequestValidator : Validator<CreateCreatorRequest>
+{
+    public CreateCreatorRequestValidator()
+    {
+        RuleFor(r => r.SlugReservationId)
+            .NotNull()
+            .NotEmpty()
+            .WithMessage("You should specify a valid SlugReservationId");
+        
+        RuleFor(r => r.CreatorId)
+            .NotNull()
+            .NotEmpty()
+            .WithMessage("You should specify a valid CreatorId");
+    }
+}
+
+[PublicAPI]
+public sealed class CreateCreatorHandler(
+    CreatorsDbContext context)
+    : Endpoint<CreateCreatorRequest>
+{
+    public override void Configure()
+    {
+        Post("/api/creators");
+        Options(o => o.WithTags("Creators"));
+    }
+
+    public override async Task HandleAsync(
+        CreateCreatorRequest req,
+        CancellationToken ct)
+    {
+        await using var transaction = await context.Database.BeginTransactionAsync(ct);
+        
+        try
+        {
+            var slug = await context
+                .Slugs
+                .SingleAsync(s => s.Id == req.SlugReservationId, ct);
+
+            if (slug.UsedBy is not null
+                || slug.ReservedUntil < DateTimeOffset.UtcNow
+                || slug.CreatedBy != User.GetUserId())
+            {
+                await SendErrorsAsync(500, ct);
+                return;
+            }
+            
+            slug.UsedBy = req.CreatorId;
+            
+            await context.Creators.AddAsync(
+                new Creator
+                {
+                    Id = req.CreatorId,
+                    CreatedBy = User.GetUserId(),
+                    Name = slug.Name,
+                    Slug = slug.NormalizedName
+                },
+                ct);
+
+            await context.SaveChangesAsync(ct);
+
+            await transaction.CommitAsync(ct);
+            
+            await SendOkAsync(ct);
+        }
+        catch (Exception)
+        {
+            await transaction.RollbackAsync(ct);
+        }
+    }
+}