Now that argocd's Authentik OAuth2 client is public, `argocd login --sso`
works for day-to-day use. Promote it to the default in AGENTS.md,
argocd-cli reference, and troubleshooting; keep the admin/password flow
documented as a break-glass fallback for when Authentik is unavailable.
Also drops --grpc-web from every interactive login command — confirmed
extraneous (login succeeds without it). Left in CI workflows and
`argocd cluster add` untouched; those are different contexts that I
didn't re-test.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
