refactor: Rename EmailPorifler to MessagingService

src/DigitalData.MessagingService.Domain/Common/DomainConstants.cs

@@ -0,0 +1,19 @@
+namespace DigitalData.MessagingService.Domain.Common;
+
+/// <summary>
+/// Domain-wide constants
+/// </summary>
+public static class DomainConstants
+{
+    /// <summary>
+    /// Email processing constants
+    /// </summary>
+    public static class Email
+    {
+        /// <summary>
+        /// Maximum number of retry attempts for failed email sending
+        /// After this limit, email will be moved to Dead Letter Queue (DLQ)
+        /// </summary>
+        public const int MaxRetryCount = 3;
+    }
+}