Conflicts resolved:
- TxQ.cpp: keep this branch's consensus.accept.apply sentence, and
take phase-3's new wording for why a lambda picks the factory.
- SpanGuardFactory.cpp: keep the SpanNames.h include; this branch's
test uses its constants.
Also fixed here, because the phase-1b changes arriving in this merge
do not compile with this branch's code:
- ScopedSpanGuard::addEvent(name, attrs) calls guard_, like its
neighbours.
- ApplicationImp::getTelemetry() is restored. The merge dropped it with
no conflict when getTelemetry() left ServiceRegistry, but Application
declares it pure virtual.
7fb2d8ec84