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.
Added new resource strings (prefix, link, suffix) for authenticator app setup instructions in German, English, and French resource files. Updated EnvelopeLocked.cshtml to assemble the instruction dynamically using these localized parts, ensuring correct grammar and flexibility across supported languages.
Added "DocumentSharingPeriodExpired" and "Expired" keys to de-DE, en-US, and fr-FR resource files. Updated EnvelopeExpired.cshtml to use localized strings for the title, heading, and message, enabling full internationalization of the expired envelope page.
Added Resource.fr-FR.resx with French UI translations. Updated EnvelopeGenerator.Application.csproj to include the new resource and copy it to the output directory, enabling French language support in the application.
