Suppress noisy pip warnings in pre-commit hook

--no-warn-script-location: bandit scripts go to /tmp/.local/bin which is
not on PATH, but we invoke via 'python -m bandit' so this is harmless.
PIP_DISABLE_PIP_VERSION_CHECK=1: silence the version upgrade notice.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.githooks/pre-commit

@@ -21,8 +21,9 @@ docker run --rm \
   -e STAGED_FILES="$STAGED" \
   -u 1001:1001 \
   -e HOME=/tmp \
+  -e PIP_DISABLE_PIP_VERSION_CHECK=1 \
   python:3.12-slim \
-  sh -c "pip install --quiet --user bandit && python scripts/security_check.py"
+  sh -c "pip install --quiet --user --no-warn-script-location bandit && python scripts/security_check.py"
 
 EXIT_CODE=$?