Vikunja before 2.6.0 continues to expose the raw TOTP shared secret after enrollment through the GET /api/v1/user/settings/totp and /api/v1/user/settings/totp/qrcode endpoints without re-authentication. Attackers with a valid access token can read the secret, import it into their own authenticator, and generate valid codes indefinitely to defeat the second factor and enable account takeover.

Affected: Go: code.vikunja.io/api

### Summary Once a user has TOTP enabled, the API still hands back the raw shared secret to anyone holding that account's access token. Reading it doesn't ask for the password, even though disabling TOTP does. So a stolen token, an XSS, or a browser left open is enough to copy the second factor into your own authenticator and keep generating valid codes indefinitely.

### Details `GET /api/v1/user/settings/totp` returns the full TOTP object, including the secret field and the otpauth:// provisioning URL. `GET /api/v1/user/settings/totp/qrcode` renders the same secret as a QR image. Neither requires re-authentication, the access token alone is enough.

This is inconsistent with the rest of the flow: `POST /api/v1/user/settings/totp/disable` calls CheckUserPassword before it will turn TOTP off. So the destructive action is gated behind the password, but reading out the secret that backs the second factor isn't. There's also no reason for the secret to be readable at all once enrollment is finished, the client only needs it during setup.

The fix is to stop returning secret/url/the QR code once enabled is true (only expose them during the enrollment window). Requiring the password on the read, like disable already does, would also be reasonable.

### PoC The attacker needs the victim's access token, from an XSS, a leaked/stolen token, or an unlocked session. TOTP must already be enabled on the account.

1. With the victim's bearer token, call: ``` GET /api/v1/user/settings/totp…