fix: Add nosec B404 comment to subprocess import

The pyproject.toml configuration with -c flag doesn't reliably suppress
B404 warnings in all CI environments. Adding the nosec comment directly
to the import line ensures consistent behavior across all environments.

B404 is a low-severity warning about importing subprocess module, which
is necessary and safe for managing OpenClaw CLI subprocess lifecycle.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: rcholic

src/predicate_secure/openclaw_adapter.py

@@ -11,7 +11,7 @@
 
 import json
 import os
-import subprocess
+import subprocess  # nosec B404
 import threading
 from collections.abc import Callable
 from dataclasses import dataclass