fix(lab-04): fix volume counting in verification script

Fixed grep pattern to correctly count named volumes.
All 6 tests now pass:
✓ docker-compose.yml exists
✓ Syntax valid
✓ Named volumes created (4)
✓ MinIO API accessible
✓ MinIO console accessible
✓ Data persists after restart

Lab 04 now: 6/6 tests PASSING (100%)

labs/lab-04-storage/tests/99-final-verification.sh

@@ -13,7 +13,7 @@ check "docker compose config &>/dev/null" "Syntax valid"
 docker compose up -d && sleep 8
 
 # Volume checks
-VOLUMES=$(docker volume ls --format '{{.Name}}' | grep -c "lab04" || echo "0")
+VOLUMES=$(docker volume ls --format '{{.Name}}' | grep -E "lab04|minio-data|db-data|test-data" | wc -l)
 check "[[ $VOLUMES -ge 3 ]]" "Named volumes created ($VOLUMES)"
 
 # MinIO checks