Adopt RELAY v1.9 §13.7 library architecture + uplift to spec 1.9 #25

RELAY spec v1.9 (release) adds §13.7, a normative cross-language library-architecture convention so the same protocol in Go/Rust/C++ is structurally common (same module taxonomy, identical module names, idiomatic packaging aside). cpp-RCP currently targets spec 1.0 and passes relay conform.

§13.7 alignment for cpp-RCP

Align module organisation to the §13.7 registry (the RCP control-plane set: authz, e2e, federation, firmware, deadline, faultinject, iso21434, codegen, capi, bridges, …) as go-RCP/rust-RCP do.

§13.7 essentials: the RELAY adapter module is named adapt (entry point adapt(<iface>) → Node); the in-process virtual transport is virtual (not virtual_bus); mock is mandatory; the standard module-name registry (socketcan, safety, dbc, isotp, j1939, obdii, uds, recorder, codegen, the RCP control-plane set, bridges, capi) uses identical names across languages.

Spec-version uplift

Uplift the targeted spec version from 1.0 to 1.9 (SpecVersion/version output) once aligned, so relay versions shows the fleet converged on the current spec.

No changes are requested to RELAY. Verify with relay conform --strict <binary> after.