parallelise: show_abstraction & ocda_db as the rest

Fix issue with consistency (flags run serial & parallel
inconsistenly).

Both write one file per document per language and share no
handle, so they belong on the list with html, epub, text and
sqlite_discrete.

The guard above the list still takes out --pod, --pod2,
--source and the shared sqlite db actions before it is reached, so
those stay serial as they were; checked.

However measurement tests show parallel turn out to result in a
processing slowdown, on the (35) sample markup documents, run on
multiple passes: run on 16 cores a slow down of about 20% for
eleven times the cpu!
  --text                           4.83-5.10 s wall   48-52 s user
  --text --serial                  3.94-4.05 s wall   4.2-4.4 s user

will make serial run the default.

(assisted by Claude-Code)

2 files changed, 13 insertions, 4 deletions

diff --git a/org/spine.org b/org/spine.org
index 86003b9..b60fd8d 100644
--- a/org/spine.org
+++ b/org/spine.org
@@ -1044,7 +1044,16 @@ struct OptActions {
        _is = false;
       }
     } else if (
+      /+ ↓ show_abstraction and ocda_db belong here for the same reason as
+           the rest: each writes one file per document per language and
+           shares no handle. --pod2 and --source, which also set
+           show_abstraction, and the shared sqlite db actions are taken out
+           by the guard above before this list is reached, so listing them
+           here does not parallelise those
+      +/
       opts["abstraction"]
+      || show_abstraction
+      || ocda_db
       || concordance
       || curate
       || html
diff --git a/org/tests_for_document_abstraction_shell_scripts.org b/org/tests_for_document_abstraction_shell_scripts.org
index 932f1cd..199e109 100644
--- a/org/tests_for_document_abstraction_shell_scripts.org
+++ b/org/tests_for_document_abstraction_shell_scripts.org
@@ -232,10 +232,10 @@ fi
 echo "Generating current .ssp files..."
 rm -rf "$TMP_DIR"
 mkdir -p "$TMP_DIR"
-# --abstraction is what puts this run in parallel: --show-abstraction on its
-# own does not appear in spine's parallelise() list, so it runs serially and
-# the parallel-vs-serial comparison below would compare a serial run with
-# itself. Do not drop it.
+# this run has to be the parallel one: the serial run below is what it is
+# compared against, and two serial runs compare nothing. --show-abstraction
+# now parallelises on its own, and --abstraction is kept as well so that the
+# test does not go quietly serial if that ever changes.
 $SPINE_BIN --abstraction --show-abstraction --skip-output --output="$SCRIPT_DIR/current" "$SAMPLES_DIR"/* 2>&1 | tail -1
 # flatten
 find "$SCRIPT_DIR/current" -name "*.ssp" ! -path "$TMP_DIR/*" -exec mv {} "$TMP_DIR/" \;