Add an explicit non-empty check before encrypting user-submitted
email/password fields in the create and update user routes, so a
request that bypasses the HTML `required` attribute gets a clean
400 instead of an unhandled ValueError from CredentialCipher.encrypt
propagating as a 500. Applies to all four credential fields on
create, and to the two email fields on update (the password-blank-
means-keep-existing behavior on update is unchanged).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
d2ac079870