Refactored EnvelopeSigned.cshtml to use a local variable for IsReadAndConfirm when setting the page title, improving readability. Also updated Razor syntax for localizer calls in <h1> and <p> elements to ensure correct evaluation and formatting.
Set model to EnvelopeReceiverDto and import required types. Update ViewData["Title"] to use DocSigned or DocConfirmed based on Envelope.IsReadAndConfirm() result.
Added new resource strings for document signing success and confirmation messages in de-DE, en-US, and fr-FR. Updated EnvelopeSigned.cshtml to use these localized strings instead of hardcoded text.
