[cpp-RCP-FS-04] Test suite certifies retired enum numeric values (Zone::FrontLeft==1, etc.) #87

Location: tests/test_rcp.cpp — "Zone constants have correct numeric values" (~lines 45-51), "CommandType constants have correct numeric values" (~lines 77-82), and the Priority ordering test (~lines 69-72); registered as part of the rcp_core test target.

Finding: The test suite includes cases that pin exact numeric values for the retired model's enums — e.g. asserting Zone::FrontLeft == 1 through Zone::Central == 5, and CommandType::Set == 1 and friends. Since these run as part of the certified/gated test suite, they effectively certify a data model with no counterpart in the current TC18-based protocol, and they'd actively resist deleting rcp.hpp's retired types (per the related finding) since removing those types would break these specific tests rather than any behavior that matters to the current protocol.

Recommendation: Delete the Zone/CommandType/Priority-numeric-value test cases, and replace the certification coverage they occupy with TC18-relevant conformance tests instead — e.g. ByteBusId range checks, ControlFlags/bit-position assertions, or ACF_ABB/ACF_GBB round-trip tests.

Verification: Independently re-read tests/test_rcp.cpp and tests/CMakeLists.txt against current HEAD (commit 4b9449a, 2026-07-29). Confirmed the cited test cases exist verbatim and are registered as part of the built/run test suite.

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