feat(models): 🎉 Add GUID field to various models

* Introduced GUID field to Database, Domain, DomainTable, Schema, Table, View, Sequence, Column, Index, Relationship, Constraint, Enum, and Script models.
* Updated initialization functions to assign new GUIDs using uuid package.
* Enhanced DCTX reader and writer to utilize GUIDs from models where available.

pkg/writers/gorm/writer.go

@@ -380,6 +380,7 @@ func (w *Writer) createDatabaseRef(db *models.Database) *models.Database {
 		DatabaseVersion: db.DatabaseVersion,
 		SourceFormat:    db.SourceFormat,
 		Schemas:         nil, // Don't include schemas to avoid circular reference
+		GUID:            db.GUID,
 	}
 }
 
@@ -396,5 +397,6 @@ func (w *Writer) createSchemaRef(schema *models.Schema, db *models.Database) *mo
 		Sequence:    schema.Sequence,
 		RefDatabase: w.createDatabaseRef(db), // Include database ref
 		Tables:      nil,                     // Don't include tables to avoid circular reference
+		GUID:        schema.GUID,
 	}
 }