🛡️ v17.1.1: fix(ci): repaired native builds broken by native audio stack deps

Added ensure-cmake action installing pinned cmake/ninja on omp-kata pods; audiopus_sys builds bundled libopus via CMake (Ninja for MSVC cross).
Set CMAKE_POLICY_VERSION_MINIMUM=3.5 globally and in build-native.ts: the bundled opus tree declares cmake_minimum_required below 3.5, which CMake 4.x refuses.
Dropped the -C target-cpu=native fallback for...