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

feat(emailer): add Postmark and Resend providers

backend/Infrastructure/Payments/Stripe/Services/MembershipTierProcessor.cs

@@ -0,0 +1,43 @@
+using Hutopy.Infrastructure.Payments.Stripe.Configuration;
+using Hutopy.Modules.Memberships.Contracts;
+using Microsoft.Extensions.Options;
+using Stripe;
+
+namespace Hutopy.Infrastructure.Payments.Stripe.Services;
+
+public sealed class MembershipTierProcessor(
+    IOptions<StripeOptions> stripeOptions) 
+    : IMembershipTierProcessor
+{
+    public async Task<string> CreateAsync(
+        Guid creatorId,
+        Guid tierId,
+        string productName,
+        string currencyCode,
+        decimal amount)
+    {
+        StripeConfiguration.ApiKey = stripeOptions.Value.SecretKey;
+
+        // Create the product
+        var productService = new ProductService();
+        var product = await productService.CreateAsync(
+            new ProductCreateOptions
+            {
+                Name = productName,
+                Metadata = { { "creatorId", creatorId.ToString() }, { "tierId", tierId.ToString() } }
+            });
+
+        // Create the price for the product
+        var priceService = new PriceService();
+        await priceService.CreateAsync(
+            new PriceCreateOptions
+            {
+                Product = product.Id,
+                UnitAmountDecimal = amount * 100, // Convert amount to cents
+                Currency = currencyCode,
+                Recurring = new PriceRecurringOptions { Interval = "month" }
+            });
+
+        return product.Id;
+    }
+}