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

feat(emailer): add Postmark and Resend providers

backend/Modules/Memberships/Handlers/SubscribeToCreator.cs

@@ -0,0 +1,83 @@
+using Hutopy.Infrastructure.Security;
+using Hutopy.Modules.Creators.Contracts;
+using Hutopy.Modules.Memberships.Contracts;
+using Hutopy.Modules.Memberships.Data;
+
+namespace Hutopy.Modules.Memberships.Handlers;
+
+[PublicAPI]
+public class SubscribeRequest
+{
+    public Guid CreatorId { get; set; }
+    public Guid MembershipTierId { get; set; }
+    public required string CheckoutSuccessUrl { get; init; }
+    public required string CheckoutCancelledUrl { get; init; }
+}
+
+[PublicAPI]
+public record struct SubscriptionResponse(
+    string StripeCheckoutUrl);
+
+[PublicAPI]
+public class SubscribeValidator : Validator<SubscribeRequest>
+{
+    public SubscribeValidator()
+    {
+        RuleFor(x => x.MembershipTierId).NotEmpty();
+    }
+}
+
+[PublicAPI]
+public class SubscribeHandler(
+    MembershipsDbContext dbContext,
+    ICreatorLookup creatorLookup,
+    IMembershipPaymentProcessor membershipPaymentProcessor)
+    : Endpoint<SubscribeRequest, SubscriptionResponse>
+{
+    public override void Configure()
+    {
+        Post("/api/memberships/subscribe");
+        Options(o => o.WithTags("Memberships"));
+    }
+
+    public override async Task HandleAsync(
+        SubscribeRequest req,
+        CancellationToken ct)
+    {
+        var tier = await dbContext
+            .MembershipTiers
+            .Where(tier => tier.Id == req.MembershipTierId)
+            .FirstOrDefaultAsync(ct);
+        if (tier == null)
+        {
+            await SendNotFoundAsync(ct);
+            return;
+        }
+
+        var creator = await creatorLookup.GetCreatorAsync(tier.CreatorId, ct);
+        if (creator == null)
+        {
+            await SendNotFoundAsync(ct);
+            return;
+        }
+
+        if (!creator.AcceptCharges)
+        {
+            await SendErrorsAsync(StatusCodes.Status400BadRequest, ct);
+            return;
+        }
+
+        // Process Stripe subscription
+        var checkoutSession = await membershipPaymentProcessor.CreateCheckoutSessionAsync(
+            User.GetUserId(),
+            creator,
+            tier.Id,
+            tier.StripePriceId,
+            req.CheckoutSuccessUrl,
+            req.CheckoutCancelledUrl);
+
+        await SendOkAsync(
+            new SubscriptionResponse { StripeCheckoutUrl = checkoutSession.Url },
+            cancellation: ct);
+    }
+}