feat(pre-push-safety-net): record admission vetoes and meet M1a on NodeGoat

Add group 9 to the approved task plan as the bounded owner amendment release
milestone M1a requires, implement the task-local recorded-veto evaluation flag,
and run the three pinned NodeGoat revisions under it.

The flag re-runs the production comparison and admission over a lifted copy of
the same evidence and records each veto instead of applying it. Recognized
completeness vetoes are lifted and logged; failures never are, because silence
from a failure is not a quiet fixed twin. It is off by default, accepted only on
explicit base/head replay, refused in Git stdin mode, labels every payload it
produces, and admits no defect even when a lifted candidate otherwise would.

M1a outcome, inside its one-week box and with expectations frozen on disk first:
the three entailed <lambda>2 witnesses are present at contributions.js 32-34; the
fixed twin was genuinely analyzed and quiet, answering its target question with
zero rows and no deadline reason while the same findings appear as base-only; the
unchanged revision was analyzed and recorded unchanged. The kill criterion did
not trigger.

Five vetoes fired and were recorded. M1a also corrected the diagnosis: with all
five lifted the detection still stops at operation_correspondence_unresolved,
because a newly introduced operation sits on a changed line and has no base
anchor. The unchanged revision resolves its base location on the same lines and
classifies as unchanged, which isolates correspondence as the mechanism. That
fifth veto was not in the earlier four-veto diagnosis and is now M1b's central
repair.

Diagnosis only. No defect admitted, no capability enabled, no gate changed, no
latency claim; the 900-second development budget cannot measure the hook gate.
Rollout and task 8.3 remain NO-GO.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

src/openultrasast/cli.py

@@ -132,6 +132,12 @@ def main(argv: list[str] | None = None) -> int:
     replay_parser.add_argument("--max-regions", type=int, default=500)
     replay_parser.add_argument("--mode", choices=("advisory", "blocking"), default="advisory")
     replay_parser.add_argument("--incomplete-coverage", choices=("allow", "block"), default="allow")
+    replay_parser.add_argument(
+        "--experimental-record-vetoes",
+        action="store_true",
+        help="explicit --base/--head replay only: record each comparison and admission veto per raw finding instead of "
+        "applying it; output is labeled experimental, changes no result and enables no hook capability",
+    )
 
     scan = subparsers.add_parser("scan", help="scan a local repository")
     scan.add_argument("path", type=Path)
@@ -235,9 +241,11 @@ def main(argv: list[str] | None = None) -> int:
             )
             if args.base and args.prior_hook:
                 parser.error("--prior-hook requires Git stdin mode")
+            if args.experimental_record_vetoes and not args.base:
+                parser.error("--experimental-record-vetoes requires explicit --base/--head replay; it is never a hook capability")
             prior_data = None
             if args.base:
-                delivery = replay(args.path, base=args.base, head=args.head, **options)
+                delivery = replay(args.path, base=args.base, head=args.head, record_vetoes=args.experimental_record_vetoes, **options)
             else:
                 # multiprocessing closes sys.stdin in its child; duplicate the Git pipe first.
                 with os.fdopen(os.dup(0), "rb") as stream: