feat(rc): advise a stale attach client without touching the endpoint

Carry the running viewport version and platform on the attach Request so the advisory names the client process rather than the serving daemon. Hold demonstrated defects as a release-maintained policy with a platform and attach role, and let the client resolve its own installed binary, printing delta-only guidance that never forces detach or prescribes a daemon restart. Unknown client versions stay silent. Source-only under the execution hold; unit and integration stages remain untagged.

Co-authored by: todlando