Successful base32 decode attaches a SHA1/6/30s Totp config to
LoginCore.totp. Bad base32 emits a warning and imports the login
without TOTP rather than skipping the row entirely.
Refactors map_row to return (Option<Item>, Option<ImportWarning>)
so a single row can produce both an item and a warning.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
c4905c5ee7