fix(ci): null-safe pending IP in SearchModal + bump python-multipart

- SearchModal.tsx: same null-IP guard as SearchBar; also search by
  friendly_name and ieee_address. Fixes Docker CI typecheck.
- python-multipart 0.0.26 -> 0.0.27 (CVE-2026-42561). Fixes
  Security pip-audit.

backend/requirements.txt

@@ -9,7 +9,7 @@ pydantic-settings==2.5.2
 python-jose[cryptography]==3.5.0
 passlib[bcrypt]==1.7.4
 bcrypt==4.0.1
-python-multipart==0.0.26
+python-multipart==0.0.27
 apscheduler==3.10.4
 python-nmap==0.7.1
 pyyaml==6.0.2