Docs: stale auth hooks links still use removed hash anchors

Two docs still point to old auth-hooks hash anchors even though the auth hooks guide now uses dedicated subpages. Current stale references in repo source: apps/docs/content/guides/api/custom-claims-and-role-based-access-control-rbac.mdx:21 apps/docs/content/guides/api/custom-claims-and-role-based-access-control-rbac.mdx:74 Both link to /docs/guides/auth/auth-hooks#hook-custom-access-token apps/docs/content/errorCodes/authErrorCodes.toml:129 This links to https://supabase.com/docs/guides/auth/auth-hooks?language=add-admin-role#hook-mfa-verification-attempt Current auth-hooks index page points to dedicated subpages instead: apps/docs/content/guides/auth/auth-hooks.mdx:24 apps/docs/content/guides/auth/auth-hooks.mdx:27 apps/docs/content/guides/auth/auth-hooks.mdx:329 apps/docs/content/guides/auth/auth-hooks.mdx:330 These use /docs/guides/auth/auth-hooks/custom-access-token-hook and /docs/guides/auth/auth-hooks/mfa-verification-hook I could not find matching hook-custom-access-token or hook-mfa-verification-attempt anchors in the current auth-hooks index source. Expected behavior: Replace the stale hash links with the current dedicated subpage routes so the RBAC guide and auth error code references resolve to the right hook pages.