Adds /konto/einstellungen, which gathers two-factor authentication,
"sign out on all devices", the Erntepost consent, the data export
(Art. 15 GDPR) and account deletion (Art. 17 GDPR) in one place.
The account overview now links there through a "Settings" card
instead of listing these blocks inline. Server actions are unchanged
apart from redirecting failures and revalidating the new page.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
