docs(decisions): handoff for parallel L0 checks; runner usage names --jobs

Co-Authored-By: Claude Opus 5.5 <[email protected]>

conformance/lib/run_l1_offline.py

@@ -14,7 +14,7 @@ Pure standard library (matches the harness's no-pip-dependency posture); the che
 themselves shell out (render checks to catalog/render.py, whose PyYAML dependency lives
 there; L0 checks to git + PyYAML).
 
-Usage: run_l1_offline.py --junit <out.xml> [--label-prefix P] <test-dir> [<test-dir> ...]
+Usage: run_l1_offline.py --junit <out.xml> [--label-prefix P] [--jobs N] <test-dir> [<test-dir> ...]
 Exit 0 iff every selected offline check passes.
 
 The per-dir check script is whichever of `render-check.sh` / `check.sh` the directory