- Add btcexplorercookiefile to BTCPay deterministic config so NBXplorer
cookie authentication succeeds (fixes 401 Unauthorized)
- Set WorkingDirectory to package lib dir so ASP.NET Core can locate
wwwroot and LanguageService.ctor does not throw ArgumentNullException
- Update regression test to assert cookie file path and WorkingDirectory
Co-authored-by: naturallaw777 <99053422+naturallaw777@users.noreply.github.com>