feat: add mfa on sign in with an authenticator app

[rthomare]

Pull Request Checklist

• Did you add new tests and confirm existing tests pass? (yarn test)
• Did you update relevant docs? (docs are found in the site folder, and guidelines for updating/adding docs can be found in the contribution guide)
• Do your commits follow the Conventional Commits standard?
• Does your PR title also follow the Conventional Commits standard?
• If you have a breaking change, is it correctly reflected in your commit message? (e.g. feat!: breaking change)
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PR-Codex overview

This PR focuses on implementing Multi-Factor Authentication (MFA) throughout the application, adding support for new MFA functionalities, and enhancing related components, documentation, and error handling.

Detailed summary

• Added useMFA hook for managing MFA operations.
• Introduced new MFA-related components and modals.
• Updated various files to support MFA, including new methods in BaseSignerClient.
• Enhanced error handling for MFA requirements.
• Updated documentation to reflect MFA changes.
• Added new tests for MFA functionalities.

The following files were skipped due to too many changes: site/pages/react/mfa/social-login.mdx, account-kit/react/src/components/auth/card/loading/totp.tsx, account-kit/react/src/components/auth/sections/EmailAuth.tsx, site/pages/react/mfa/email-otp.mdx, account-kit/signer/test/mocks/MockAlchemySignerWebClient.ts, examples/ui-demo/src/components/ui/OTPInput.tsx, site/sidebar/reference/account-kit/signer.ts, site/pages/react/mfa/email-magic-link.mdx, site/pages/signer/authentication/mfa.mdx, examples/ui-demo/src/components/modals/MFA/MFAModal.tsx, examples/ui-demo/src/components/icons/google-play.tsx, account-kit/signer/src/client/index.ts, site/pages/react/mfa/setup-mfa.mdx, account-kit/signer/test/base.test.ts, examples/ui-demo/src/components/icons/app-store.tsx, examples/ui-demo/src/components/icons/alchemy-two-tone.tsx, account-kit/signer/src/base.ts, examples/ui-demo/src/components/ui/Spinner.tsx

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[blakecduncan]

LGTM