Consider supporting OTP links for setting up TFA OTP Codes

> Both iOS and macOS handle a special URL based on the industry standard otpauth specification. The Apple-specific version of this URL is identical to the standard, but uses the apple-otpauth: scheme. Embed this URL in your webpages and apps to allow your users to set up new code generators directly in the iCloud Keychain password manager with minimal effort. On the web, use an tag to create a link. – From [iCloud Keychain Verification Codes](https://developer.apple.com/documentation/AuthenticationServices/securing-logins-with-icloud-keychain-verification-codes)

I'm not sure how much I care about this since we have passkey support but I'll leave it here in case others are interested (please comment) or I find a reason to care later.

Look at the TFA (two-factor authentication) setup flow in the codebase, likely in a module handling OTP generation. Research the otpauth URI format and how to generate QR codes or links. Check if there's existing support for passkeys to understand the authentication structure. Implement support for otpauth links, ensuring they work with both standard and Apple-specific schemes, and test the setup process.

Scritto dal modello di indicizzazione a partire dal testo della issue.