Lockstep major across dvb-common/dvb-si/dvb-t2mi/dvb-bbframe. Full typing of
the last raw structured loops, section-length DoS hardening, four runtime
registries + un-sealed *Def traits, non_exhaustive sweep, unified error model,
removal of dead legacy traits and redundant wire-count fields. See
docs/release-notes/v5.0.0.md.