Introduced the `UnitOfLength` enum to represent measurement units
(Inch and Point) for signature positioning, with detailed
documentation and conversion logic.
Updated `SignatureDto` to use `init` accessors for immutability,
added backing fields for `X` and `Y` with conversion support, and
introduced the `Factor` property to handle unit conversions.
Added a `Convert` method to enable switching between units of
length and improved extensibility for future `SenderAppType`
support. Enhanced code readability and maintainability with
detailed comments and remarks.
A new `SenderAppType` enum was introduced in the
`EnvelopeGenerator.ReceiverUI.Models.Constants` namespace, with
values `LegacyFormApp` and `ReceiverUIBlazorApp`.
The `SignatureDto` class was updated to include a new property of
type `SenderAppType`, enabling the specification of the sender
application type for a signature.
Additionally, a `using` directive for the
`EnvelopeGenerator.ReceiverUI.Models.Constants` namespace was added
to `SignatureDto.cs` to support the use of the new enum.
