refactor(pdf-burner): organize code with regions for better readability

- Grouped related methods and classes into logical #Region blocks:
  - "Burn PDF"
  - "Add Value"
  - "Helpers"
  - "Model"
- Improved code structure and readability without changing functionality.
- No logic or behavior modifications were made.

EnvelopeGenerator.CommonServices/Jobs/FinalizeDocument/PDFBurner.vb

@@ -36,6 +36,7 @@ Namespace Jobs.FinalizeDocument
             _pdfBurnerParams = pdfBurnerParams
         End Sub
 
+#Region "Burn PDF"
         Public Function BurnAnnotsToPDF(pSourceBuffer As Byte(), pInstantJSONList As List(Of String), envelopeId As Integer) As Byte()
             'read the elements of envelope with their annotations
             Dim sigRepo = Factory.Shared.Repository(Of Signature)()
@@ -93,7 +94,9 @@ Namespace Jobs.FinalizeDocument
                 End Using
             End Using
         End Function
+#End Region
 
+#Region "Add Value"
         Private Sub AddInstantJSONAnnotationToPDF(pInstantJSON As String)
             Dim oAnnotationData = JsonConvert.DeserializeObject(Of AnnotationData)(pInstantJSON)
 
@@ -175,7 +178,9 @@ Namespace Jobs.FinalizeDocument
             ant.FontStyle = _pdfBurnerParams.FontStyle
             Manager.SaveAnnotationsToPage()
         End Sub
+#End Region
 
+#Region "Helpers"
         Private Function ToPointF(pPoints As List(Of Single)) As PointF
             Dim oPoints = pPoints.Select(AddressOf ToInches).ToList()
             Return New PointF(oPoints.Item(0), oPoints.Item(1))
@@ -188,7 +193,9 @@ Namespace Jobs.FinalizeDocument
         Private Function ToInches(pValue As Single) As Single
             Return pValue / 72
         End Function
+#End Region
 
+#Region "Model"
         Friend Class AnnotationData
             Public Property annotations As List(Of Annotation)
 
@@ -318,5 +325,6 @@ Namespace Jobs.FinalizeDocument
             Public Property name As String
             Public Property value As String
         End Class
+#End Region
     End Class
 End Namespace