- Restore ccache with WarpBuilds/cache@v1 on all three OS and the
dynamic-backend job (per-OS keys with branch fallback), and wire it
up through CMAKE_C/CXX_COMPILER_LAUNCHER; builds print ccache -s so
hit rates are visible in CI logs
- Cache the macOS OpenTimelineIO build (keyed on v0.16.0) and skip the
rebuild on cache hit
- Install ccache via apt/brew/MSYS2 as needed; CCACHE_MAXSIZE=1G
- Runner sizes 16x/32x -> 8x (macOS 12x kept); openfx-misc make -j8 to
match