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

feat(emailer): add Postmark and Resend providers

backend/Modules/Tipping/Data/Tip.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+using Hutopy.Common.Domain;
+
+namespace Hutopy.Modules.Tipping.Data;
+
+public class Tip : Entity
+{
+    public Guid CreatorId { get; set; }
+    public TipStatus Status { get; set; }
+    public decimal Amount { get; set; }
+    [MaxLength(8)] public required string Currency { get; set; }
+    [MaxLength(2048)] public required string Message { get; set; }
+    [MaxLength(256)] public required string StripeSessionId { get; set; }
+    [MaxLength(2048)] public string? StripeInvoiceUrl { get; set; }
+}
+
+public enum TipStatus : short
+{
+    Pending = 0,
+    Paid = 1,
+}