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)

test-abstraction-ssp.sh should fail if $SpinePOD is unset.

SAMPLES_RAW="$SPINE_DIR/$SpinePOD" resolves to the spine directory
itself when the variable is unset. That directory exists, so the
"sample documents not found" check did not fire and spine was
handed every file in the spine tree.

Fail early instead, naming the variable and giving the path the
samples are usually at.

(assisted by Claude-Code)

- test/test-abstraction-ssp.sh script minor improvement

- result change reflects content corrections: name spelling & a markup
  error, document abstracton, ssp verified ok (may be considered a test)

(assisted by Claude-Code)

- odd hilighting issue ... must result from my org config, but "fix"
  makes things easier for me.

test/test-abstraction-ssp.sh: shell script that generates
.ssp files for all sample documents and diffs against
committed reference files in test/reference/abstraction/.

Usage:
  ./test/test-abstraction-ssp.sh --generate ./bin/spine-ldc
  ./test/test-abstraction-ssp.sh ./bin/spine-ldc

Exits 0 if all .ssp files match, 1 if differences found.
Reports changed, missing, and new files.

test/reference/abstraction/: 35 reference .ssp files
generated from the current abstraction, covering all
sample documents including 9-language live-manual.

Co-Authored-By: Anthropic Claude Opus 4.6 (1M context)