v0.10.2

Changed

• barrel_mcp and barrel_a2a are no longer top-level dependencies.
  They were optional at runtime since 0.10.0 but still fetched and
  locked by every project depending on livery. An application that uses
  livery_mcp or livery_a2a adds the library to its own deps. The
  test profile pulls them for the suites, and xref and dialyzer run
  under the new check profile (rebar3 as check xref).