* Implement V2 registration support
* Require the client version header on every login, like upstream
Every user login (password, user API key, SSO, including a first SSO login)
now needs the Bitwarden-Client-Version header, for V1 accounts too. V2
accounts need 2026.10.1, or 2026.10.2 for the desktop app, upstream's
current minimum.
* Escape the email in the client version log line
On a first SSO login the email comes from the identity provider and isn't validated yet, so a newline in it could add a line to the log.