Refactor contract type handling in EnvelopeType entity

Replaced Constants.ContractType enum with integer property in EnvelopeType. Updated related references in EnvelopeEditorController. Removed EnvelopeType variable from ModuleSettings. Made EnvelopeType property bindable and initialized in frmEnvelopeMainData to improve consistency and simplify contract type management.

EnvelopeGenerator.Domain/Entities/EnvelopeType.cs

@@ -56,7 +56,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public int ReminderIntervalDays { get; set; } = 0;
 
         [Column("CONTRACT_TYPE")]
-        public Constants.ContractType ContractType { get; set; }
+        public int ContractType { get; set; }
 
         [NotMapped]
         public bool TFA_Enabled { get; set; } = false;