The Run tests step captured $? after piping xcodebuild through tee,
which always exits 0, so a failing build or test run reported as a
pass. Use ${PIPESTATUS[0]} to read xcodebuild's real exit code.

Also bump the selected Xcode from 26.2 to 26.4 so CI matches the
version the committed prebuilt binary dependencies were built with;
otherwise the dependency build phase regenerates them and fails.