feat(mvp): working secrets-engine CLI for the whynot-design npm publish lane

Implements SECRETS-WP-0002 end to end as a uv-managed Python package:

- catalog: non-secret lane registry + strict validator (build/test/prod)
- stage roles + OpenBao ACL policies; guards refuse wildcards, sys/, identity/,
  admin names, and cross-stage paths before any backend call
- plan/apply: dry-run-first, idempotent policy + approle apply, decision-gated
- decisions: State Hub lookup with local-fixture fallback; non-secret evidence
  to JSONL + hub progress, scrubbed of any value
- provision/verify: mode-0600 file import + generated test values; positive/
  negative checks that never print the value
- exec delivery: `exec --catalog ... -- npm publish` injects the token via a
  temp .npmrc for the child only, cleaned up on exit/failure/interrupt
- ops-warden routing contract + hardening backlog docs
- 34 tests incl. live OpenBao integration; scripts/demo-e2e.sh runs the full
  chain against a throwaway bao dev server

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_decisions.py

@@ -0,0 +1,52 @@
+import pytest
+
+from secrets_engine.catalog import validate_entry
+from secrets_engine.decisions import Decision, require_approved, resolve_decision
+from secrets_engine.errors import DecisionError
+
+from tests.test_catalog import VALID
+
+
+def _approved(model="decision"):
+    d = dict(VALID, approval={"model": model, "decision_ref": "x"})
+    return validate_entry(d)
+
+
+def test_bootstrap_only_needs_no_decision():
+    e = validate_entry(dict(VALID, approval={"model": "bootstrap-only"}))
+    require_approved(e, None)  # must not raise
+
+
+def test_unapproved_decision_refused():
+    e = _approved()
+    d = Decision(id="d", title="t", status="pending", superseded_by=None, source="hub")
+    with pytest.raises(DecisionError):
+        require_approved(e, d)
+
+
+def test_superseded_decision_refused():
+    e = _approved()
+    d = Decision(id="d", title="t", status="resolved", superseded_by="d2", source="hub")
+    with pytest.raises(DecisionError):
+        require_approved(e, d)
+
+
+def test_approved_decision_passes():
+    e = _approved()
+    d = Decision(id="d", title="t", status="resolved", superseded_by=None, source="hub")
+    require_approved(e, d)  # must not raise
+
+
+def test_local_fixture_resolves(tmp_path):
+    (tmp_path / ".decisions").mkdir()
+    (tmp_path / ".decisions" / "myref.yaml").write_text(
+        "id: myref\ntitle: t\nstatus: resolved\nsuperseded_by: null\n"
+    )
+    d = resolve_decision(hub_url="http://127.0.0.1:1", repo_root=tmp_path, decision_ref="myref")
+    assert d.source == "local-fixture"
+    assert d.is_approved()
+
+
+def test_missing_decision_raises(tmp_path):
+    with pytest.raises(DecisionError):
+        resolve_decision(hub_url="http://127.0.0.1:1", repo_root=tmp_path, decision_ref="nope")