chore: add macOS 26.4

chore: add macOS 26.3

chore: Add support for macOS 26.2

Updates CI workflow, build script, and README to include macOS 26.2 (build 25C56). Also improves KDK detection in
CoreEntitlements setup script to automatically find any installed 26.x KDK instead of hardcoding specific version paths.

fix: stabilize macOS 26.1 xnu build

- let build.sh prefer versioned patches with fallback and feed hw overrides into installhdrs
- make coreentitlements setup honor KDKROOT and 26.1/26.0 KDKs
- drop bash process substitution around dsymutil to avoid /dev/fd EPERM
- simplify sanitizer lipo step to prevent _SC_ARG_MAX failures

chore: add 26.0

chore: add 15.6 (missing KDK)

Update c-cpp.yml

chore: add 15.4

chore: add 15.3 stub

Update README.md