feat: complete local layer model v0.7 conformance work

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a06eaf-3425-7f92-a0c2-bb4aa4faebe4

src/warden/cli.py

@@ -2,7 +2,6 @@
 from __future__ import annotations
 
 import json
-import os
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
 from typing import Annotated, List, Optional
@@ -1309,7 +1308,9 @@ def _access_proxy(
 
     # T04 — agent identity on a high-risk lane: never stream raw secret data.
     # Agents may use sanctioned transports (--out / --exec / --wrap / --fingerprint).
-    agent_id = os.environ.get("WARDEN_AGENT_ID", "").strip()
+    from warden.access import agent_read_boundary_identity
+
+    agent_id = agent_read_boundary_identity()
     raw_value_stream = (
         not is_login and not do_exec and not wrap and not out_path and not fingerprint
     )