Introduced SignatureLinkText property in EmailData to hold signature-related text, set dynamically based on envelope type. Updated constructor to HTML-encode SignatureLinkText. Added [SIGNATURE_LINK_TEXT] to template dictionary in TemplateService for email customization.
Move dynamic message and signature type logic from TemplateService to EmailData via DynamicStringsForEmails. Constructors now set and HTML-encode these properties. Improves maintainability by centralizing email content generation.
Introduced EnvelopeTypeId as a read-only property in EmailData, set during construction. Updated TemplateService.InitDictionary to use EnvelopeTypeId for determining signature type and message content, replacing the hardcoded [SIGNATURE_TYPE] value. Also added necessary imports for domain entities and constants.
