Add governed test plane and close T04/T08

Encode fail-closed admission, target registrations, and a credential
broker that never returns secret values. Calibrate audit-core shaped
probes in-process. Send no packets and request no live credentials.

Assistant: grok
Assistant-Session: 01a02670-3345-76f2-a014-70fde8e2a2bb

src/whitehat_security/audit_fixtures.py

@@ -0,0 +1,83 @@
+from __future__ import annotations
+
+from copy import deepcopy
+from dataclasses import dataclass
+
+from .differential import DifferentialProbe
+from .model import Response
+
+
+@dataclass
+class AuditFixture:
+    """In-process audit-core shape used to calibrate the E2 pack. No sockets."""
+
+    enforce_tenant: bool
+
+    def __post_init__(self) -> None:
+        self.events = {
+            "event-a": {
+                "id": "event-a", "tenant": "tenant-a",
+                "correlation_id": "corr-shared", "label": "fixture-a",
+            },
+            "event-b": {
+                "id": "event-b", "tenant": "tenant-b",
+                "correlation_id": "corr-shared", "label": "fixture-b",
+            },
+        }
+
+    def snapshot_events(self) -> object:
+        return deepcopy(self.events)
+
+    def _visible(self, actor_tenant: str, item: dict) -> bool:
+        return (not self.enforce_tenant) or item["tenant"] == actor_tenant
+
+    def get(self, actor_tenant: str, event_id: str) -> Response:
+        item = self.events.get(event_id)
+        if item is None or not self._visible(actor_tenant, item):
+            return Response(404, {"error": "not_found"})
+        return Response(200, deepcopy(item))
+
+    def by_correlation(self, actor_tenant: str, correlation_id: str) -> Response:
+        items = [
+            deepcopy(item) for item in self.events.values()
+            if item["correlation_id"] == correlation_id and self._visible(actor_tenant, item)
+        ]
+        return Response(200, {"events": items})
+
+    def append(self, actor_tenant: str, event: dict) -> Response:
+        if self.enforce_tenant and event["tenant"] != actor_tenant:
+            return Response(403, {"error": "forbidden"})
+        self.events[event["id"]] = deepcopy(event)
+        return Response(202, {"id": event["id"], "tenant": event["tenant"]})
+
+
+def audit_probe_suite(service: AuditFixture) -> list[DifferentialProbe]:
+    markers = ("event-b", "tenant-b", "fixture-b")
+    forged = {
+        "id": "event-forged-b", "tenant": "tenant-b",
+        "correlation_id": "corr-shared", "label": "fixture-forged",
+    }
+    return [
+        DifferentialProbe(
+            "audit-event-by-id", "read",
+            lambda: service.get("tenant-b", "event-b"),
+            lambda: service.get("tenant-a", "event-b"),
+            lambda: service.get("tenant-a", "absent"),
+            markers,
+        ),
+        DifferentialProbe(
+            "audit-correlation-slice", "read",
+            lambda: service.by_correlation("tenant-b", "corr-shared"),
+            lambda: service.by_correlation("tenant-a", "corr-shared"),
+            lambda: service.by_correlation("tenant-a", "corr-absent"),
+            markers, hide_existence=False,
+        ),
+        DifferentialProbe(
+            "audit-append-as-b", "create",
+            lambda: Response(202, {"id": "owner-control"}),
+            lambda: service.append("tenant-a", forged),
+            lambda: Response(403, {"error": "forbidden"}),
+            markers + ("event-forged-b",),
+            state=service.snapshot_events, hide_existence=False,
+        ),
+    ]