fix: Add missing 'import re' to agent_scan_routes.py

NameError: name 're' is not defined at line 146 — the import was
accidentally removed when extracting helper functions to agent_scan_helpers.py.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-compliance/compliance/api/agent_scan_routes.py

@@ -7,6 +7,7 @@ POST /api/compliance/agent/scan
 
 import logging
 import os
+import re
 from datetime import datetime, timezone
 
 import httpx