Removed the placeholder option from the envelope type dropdown to simplify the UI. Introduced a new `GetDefaultEnvelopeTypeId()` method to centralize and enhance the logic for determining the default envelope type. This method prioritizes envelope types with titles containing "Handwritten Signature" if available, improving alignment with user preferences. Updated `_selectedEnvelopeTypeId` initialization to use the new method for better maintainability.
Introduce a 4-step modal wizard on SenderPage for creating envelopes.
Validate required fields, support optional skip, receiver management, PDF upload, and keyboard shortcuts.
Persist wizard payload in sessionStorage via token-based bootstrap service and navigate to editor with bootstrapToken.
Register bootstrap storage service in both client and server DI containers and add dedicated sender wizard styling.
