The header's ObservedTech notes carried a std::string size of 0x18. That was a
mis-attribution: the element's +0x24 word is the name string's trailing (empty)
allocator, not a data field. sizeof(std::string) is 0x1c binary-wide, confirmed
against every serializer in the original.
ObservedTech is now fully mapped, so the two research-hook comments that said
sizeof and the append site were unpinned are corrected. The region stays
declared-not-modelled -- appending is a behavioural change this hook does not
make -- but its byte delta now has an exact expected value (44 per completion),
and the note records that the original's append de-duplicates by tech name, so a
naive push_back would diverge on re-observation.
clean_room_check: OK. host ctest: 33/33.