The browser's Better Auth client: sign-up, sign-in (email and Google),
password reset, sign-out and session reads, against /api/auth on the
current origin.
Remarks
The account forms call it directly rather than through Server Actions: it
already handles cookies, the OAuth redirect and extra request headers such
as the Turnstile token (x-captcha-response).
The browser's Better Auth client: sign-up, sign-in (email and Google), password reset, sign-out and session reads, against
/api/authon the current origin.