.ssp: doc structure related fixes (& to epub toc_nav)

for document abstraction and its .ssp output, removed the
requirement of including --abstraction & --serial flags to produce
correct output (for: .dom_status, .dom_status_collapsed &
.last_descendant)

- meta_processing_xml_dom() includes show_abstraction, so --pod2
  and --show-abstraction run the dom pass; last_descendant is
  derived from that pass via after_doc_get_descendants()

The accumulators are now verified as eight wide locals of
docAbstraction(), so each document starts clean and no two threads
share one.
- bug: the four dom accumulators were template scope (shared) and
  nine wide, while their end of document reset was eight wide, so
  the first document of a run differed from the rest and parallel
  runs raced on one buffer, (which also mis-nested epub toc_nav)

test/ reference .ssp regenerated: accelerando only, trailing zero
dropped.
test-abstraction-ssp.sh now runs parallel and diffs output against
a serial run.

(assisted by Claude-Code)

0 files changed, 0 insertions, 0 deletions