Add ThirdPartyModule entity for 3rd party module tracking

- Created ThirdPartyModule class in EnvelopeGenerator.Domain.Entities
- Mapped to TBDD_3RD_PARTY_MODULES table with appropriate columns
- Added properties: Id, Active, Name, Description, License, Version, AddedWho, AddedWhen, ChangedWho, ChangedWhen
- Configured data annotations for primary key, required fields, string lengths, and nullable support
- Conditional nullable support based on compilation symbols

EnvelopeGenerator.Domain/Entities/ThirdPartyModule.cs

@@ -0,0 +1,73 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+#if NETFRAMEWORK
+using System;
+#endif
+
+namespace EnvelopeGenerator.Domain.Entities
+{
+    [Table("TBDD_3RD_PARTY_MODULES")]
+    public class ThirdPartyModule
+    {
+        [Key]
+        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+        [Column("GUID")]
+        public int Id { get; set; }
+
+        [Required]
+        [Column("ACTIVE")]
+        public bool Active { get; set; }
+
+        [Required]
+        [StringLength(50)]
+        [Column("NAME")]
+        public string Name { get; set; }
+
+        [StringLength(500)]
+        [Column("DESCRIPTION")]
+        public string
+#if nullable
+            ?
+#endif
+            Description { get; set; }
+
+        [Required]
+        [Column("LICENSE", TypeName = "varchar(max)")]
+        public string License { get; set; }
+
+        [Required]
+        [StringLength(20)]
+        [Column("VERSION")]
+        public string Version { get; set; }
+
+        [StringLength(50)]
+        [Column("ADDED_WHO")]
+        public string
+#if nullable
+            ?
+#endif
+            AddedWho { get; set; }
+
+        [Column("ADDED_WHEN")]
+        public DateTime
+#if nullable
+            ?
+#endif
+            AddedWhen { get; set; }
+
+        [StringLength(50)]
+        [Column("CHANGED_WHO")]
+        public string
+#if nullable
+            ?
+#endif
+            ChangedWho { get; set; }
+
+        [Column("CHANGED_WHEN")]
+        public DateTime
+#if nullable
+            ?
+#endif
+            ChangedWhen { get; set; }
+    }
+}