[cpp-RCP-FS-02] README Quick Start teaches the retired Zone/Command/Registry model #85

Location: README.md — "Quick start" section (~lines 94-127).

Finding: The "Quick start" section — the first code example a new user of this library is likely to copy — is built entirely on the retired Zone/Command/Registry model: it includes <rcp/legacy_mock.hpp>, looks up a controller by rcp::Zone::FrontLeft, builds an rcp::Command with a zone/type/priority, and checks resp.status == rcp::ResponseStatus::OK. Per the project's own tracked understanding of the relevant RELAY conformance rule, a conformant implementation isn't supposed to still surface the retired model at all, let alone use it as the first thing a new user sees.

Recommendation: Replace the quick-start example with one built on the actual TC18 model — e.g. rcp::mock::Server for an in-process server, acf::AcfMessageInfo for message construction, stream_key/byte_bus_id addressing, and the relay::Caller adapter in rcp/adapt.hpp — so the first thing a new reader learns is the currently-supported API, not the retired one.

Recommendation cross-reference: This should land together with (or after) the related finding about rcp.hpp still defining the retired model as compiled public API, since the quick-start currently exists specifically because that model is still buildable.

Verification: Independently re-read README.md's Quick Start section against current HEAD (commit 4b9449a, 2026-07-29). Confirmed it still uses rcp::Zone, rcp::CommandType, rcp::Priority, and <rcp/legacy_mock.hpp> throughout.

Filed from the 2026-07-29 ecosystem audit register; independently re-verified against current HEAD before filing.