Add a CI step to build GTSAM 4.2.1, libnabo 1.1.2 and libpointmatcher
1.4.4 from source (not available/usable from Homebrew), with patches
under .github/patches fixing Eigen 5 / Boost compatibility.
Installs are staged via DESTDIR into an actions/cache directory and
copied into /usr/local. The cache key includes the pinned versions, the
patch hashes, and the linked Homebrew (eigen/boost/yaml-cpp) + Xcode
toolchain versions, so the deps rebuild only when something relevant
changes. Also add yaml-cpp brew dep and drop the unused extra_deps
matrix field.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>