Fix health check path mismatch causing 404s

The app maps health checks at /health (ServiceDefaults), not /api/v1/health.
Compose healthcheck and deploy-qa.sh's wait-loop both hit the wrong path.
Also add an nginx location for /health since it lives outside the /api
prefix that the admin proxy otherwise forwards unchanged.

scripts/ci/deploy-qa.sh

@@ -26,7 +26,7 @@ $COMPOSE up -d
 
 log "Waiting for API health check via admin proxy on port $QA_ADMIN_PORT"
 attempts=30
-until curl -fsS "http://localhost:${QA_ADMIN_PORT}/api/v1/health" >/dev/null 2>&1; do
+until curl -fsS "http://localhost:${QA_ADMIN_PORT}/health" >/dev/null 2>&1; do
   attempts=$((attempts - 1))
   if [[ "$attempts" -le 0 ]]; then
     fail "QA stack did not become healthy in time"