9th silent-failure bug: the version stamp was checked BEFORE the real code marker
(Qt .cmake.conf / KDE KF_VERSION). A code-only revert leaves the stamp stale, and
the stale stamp then reported the module 'consistent' -> the engine skipped a
needed rebase and the validator false-passed a divergent tree. Both now check the
authoritative code marker first and use the stamp only as a fallback for
marker-less trees. The validator also learned KDE's KF_VERSION marker. Test E21.
vasilito
6c25f4dd06