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

feat(emailer): add Postmark and Resend providers

backend/Modules/Creators/Features/GetCreatorById.cs

@@ -0,0 +1,48 @@
+using Hutopy.Modules.Creators.Data;
+
+namespace Hutopy.Modules.Creators.Features;
+
+[PublicAPI]
+public sealed class GetCreatorByIdRequest
+{
+    public required Guid CreatorId { get; set; }
+}
+
+[UsedImplicitly]
+public sealed class GetCreatorByIdRequestValidator
+    : Validator<GetCreatorByIdRequest>
+{
+    public GetCreatorByIdRequestValidator()
+    {
+        RuleFor(r => r.CreatorId)
+            .NotNull().WithMessage("You should specify the CreatorId")
+            .NotEmpty().WithMessage("You should specify a valid/not empty CreatorId");
+    }
+}
+
+[PublicAPI]
+public class GetCreatorByIdHandler(
+    CreatorsDbContext context)
+    : Endpoint<GetCreatorByIdRequest, Creator>
+{
+    public override void Configure()
+    {
+        Get("/api/creators/{CreatorId}");
+        Options((o => o.WithTags("Creators")));
+        AllowAnonymous();
+    }
+
+    public override async Task HandleAsync(
+        GetCreatorByIdRequest req,
+        CancellationToken ct)
+    {
+        var creator = await context
+            .Creators
+            .FindAsync(
+                [req.CreatorId],
+                cancellationToken: ct);
+
+        if (creator is null) await SendNotFoundAsync(ct);
+        else await SendAsync(creator, cancellation: ct);
+    }
+}