Fail closed when managed OpenAI OAuth refresh fails instead of silently falling back to stale external Codex CLI credentials.
Make managed provider OAuth authoritative after bootstrap, preserve API-key and non-OpenAI external CLI behavior, and surface targeted re-auth guidance without exposing profile IDs in group/channel replies.
Fixes#99120.
Co-authored-by: Eva <239388517+100yenadmin@users.noreply.github.com>