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

feat(emailer): add Postmark and Resend providers

backend/Modules/Memberships/Handlers/CreateMembershipTier.cs

@@ -0,0 +1,56 @@
+using Hutopy.Modules.Memberships.Contracts;
+using Hutopy.Modules.Memberships.Data;
+
+namespace Hutopy.Modules.Memberships.Handlers;
+
+[PublicAPI]
+public record struct CreateMembershipTierRequest(
+    Guid CreatorId,
+    string Name,
+    string Description,
+    decimal Price,
+    string Currency = "CAD");
+
+[PublicAPI]
+public class CreateMembershipTierEndpoint(
+    MembershipsDbContext dbContext,
+    IMembershipTierProcessor membershipTierProcessor)
+    : Endpoint<CreateMembershipTierRequest>
+{
+    public override void Configure()
+    {
+        Post("/api/memberships/tiers");
+        Options(o => o.WithTags("Memberships"));
+    }
+
+    public override async Task HandleAsync(
+        CreateMembershipTierRequest req,
+        CancellationToken ct)
+    {
+        var tierId = Guid.CreateVersion7();
+
+        var productId = await membershipTierProcessor.CreateAsync(
+            req.CreatorId,
+            tierId,
+            req.Name,
+            req.Currency,
+            req.Price);
+
+        // Record the new Tier
+        var tier = new MembershipTier
+        {
+            Id = tierId,
+            CreatorId = req.CreatorId,
+            Price = req.Price,
+            Name = req.Name,
+            Description = req.Description,
+            StripeProductId = productId,
+        };
+
+        dbContext.MembershipTiers.Add(tier);
+
+        await dbContext.SaveChangesAsync(ct);
+
+        await SendOkAsync(tier, ct);
+    }
+}