feat: add MyAccount API client support

[yogeshchoudhary147]

The myAccount client introduced in auth0-spa-js#1615 was not yet surfaced through the React SDK. This PR exposes it so it is accessible via useAuth0.

Changes

useAuth0().myAccount (new)

Factors

• getFactors(): list all MFA factors enabled on the tenant with their type and usage

Authentication methods

• getAuthenticationMethods(type?): list enrolled methods, optionally filtered by type
• getAuthenticationMethod(id): get a single method by ID
• updateAuthenticationMethod(id, data): update name or preferred_authentication_method
• deleteAuthenticationMethod(id): remove an enrolled method

Enrollment (two-step)

• enrollmentChallenge(options): initiate enrollment for any factor type; returns challenge data (WebAuthn creation options, barcode URI, recovery code, password policy, etc.)
• enrollmentVerify(options): confirm enrollment; returns the created AuthenticationMethod

Supports: passkey, webauthn-platform, webauthn-roaming, phone, email, totp, push-notification, recovery-code, password.

Implementation pattern

myAccount follows the same pattern as mfa — a useMemo(() => client.myAccount, [client]) passthrough. No useCallback wrappers or GET_ACCESS_TOKEN_COMPLETE dispatches are needed since none of these operations affect isAuthenticated or user.

Exports

MyAccountApiClient (type) and MyAccountApiError are now exported from the package root.

Dependency

Bumps @auth0/auth0-spa-js to ^2.21.1.

Test plan

Manual: authentication methods CRUD

• getAuthenticationMethods() / getAuthenticationMethods("passkey"): correct fields, filtering works
• getAuthenticationMethod(id): correct shape
• updateAuthenticationMethod(id, { name }): confirmed working for totp
• deleteAuthenticationMethod(id): secondary methods deleted; primary passkey deletion correctly rejected
• getFactors(): all enabled factors returned with correct type and usage

Manual: end-to-end passkey enrollment

• User logs in with username/password (PKCE)
• User enrolls a passkey via enrollmentChallenge + enrollmentVerify
• User logs out, then logs back in via auth0.passkey.login() with no password required

Regression

• connectAccountWithRedirect + handleRedirectCallback: connected accounts flow unaffected
• auth0.passkey.signup() / auth0.passkey.login(): passkey flows unaffected