2026.11.13.1: toolchain payloads as data, build directories by lineage, UEFI through openkal, test feedback (mcpp#927), end-to-end cases in C++ with places and capabilities (mtest 0.8.0), canaries

2026.11.13.1: toolchain payloads as data, build directories by lineage, UEFI through openkal, test feedback (mcpp#927), end-to-end cases in C++ with places and capabilities (mtest 0.8.0), canaries #629