feat: integrate durable authorization audit and runtime composition

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a0e747-8f27-7242-8df8-8bc44f88c929

hub_core/security/policy.py

@@ -92,6 +92,20 @@ def _time(value: str) -> datetime:
 def verify_decision(envelope: dict, *, request: dict, keys: dict,
                     caller: str, now: datetime | None = None) -> Decision:
     verify_signature(envelope, keys)
+    # The exact signed artifact is retained for independent verification. Do
+    # not hide secret-shaped fields in its serialized audit representation.
+    def check_fields(value):
+        if isinstance(value, dict):
+            for key, item in value.items():
+                if any(fragment in key.lower() for fragment in (
+                    "password", "secret", "token", "credential", "private_key",
+                )):
+                    raise ValueError("sensitive decision field is outside the audit profile")
+                check_fields(item)
+        elif isinstance(value, list):
+            for item in value:
+                check_fields(item)
+    check_fields(envelope)
     now = now or datetime.now(timezone.utc)
     if (envelope["contract_version"] != "flex-auth.decision-record.v1"
             or envelope["request_id"] != request["id"] or not envelope["id"]):
@@ -132,7 +146,8 @@ def verify_decision(envelope: dict, *, request: dict, keys: dict,
         if (lifetime["kind"] != "ttl" or not
                 _time(lifetime["not_before"]) <= now < _time(lifetime["expires_at"])):
             raise ValueError("invalid decision lifetime")
-    return Decision(envelope["effect"] == "allow", envelope["id"], provenance["policy_version"], caller)
+    return Decision(envelope["effect"] == "allow", envelope["id"], provenance["policy_version"],
+                    caller, go_json(envelope).decode())
 
 
 class FlexPolicy: