Dual-lane dirs: .llmmsg-env LLMMSG_AGENT is a cc-lane runtime artifact (ccs.sh rewrites it) read as identity by 17+ scripts; CA identity has no on-disk existence

bin-venus-cc trace 2026-08-22 (tag bin-venus-cc-mt41cge82aqo). Nothing broken today (ca.sh exports label, beats env). Fix order: (a) non-launcher consumers read .agent-name for identity; .llmmsg-env keeps transport only; (b) if the hook needs a persisted anchor, ccs.sh writes LLMMSG_AGENT_CC (named as cc-lane). Needs a ca-side guard equivalent to MSG-84 if .llmmsg-env ever carries a ca value. Touches ccs.sh persist block + readers - coordinated change, mine.