Reproduces Node CLI’s literal-string check in config.command.ts: the strings
"null", "bitwarden.com", and "https://bitwarden.com" collapse to a missing
server (i.e. fall back to the default cloud URL on read).
Reproduces Node CLI’s formatUrl from default-environment.service.ts:
empty input collapses to None, trailing slashes are stripped, https://
is prepended when no scheme is present, and surrounding whitespace is trimmed.