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.

deploy/qa/docker-compose.qa.yml

@@ -36,7 +36,7 @@ services:
       db:
         condition: service_healthy
     healthcheck:
-      test: ["CMD-SHELL", "curl -fsS http://localhost:8080/api/v1/health || exit 1"]
+      test: ["CMD-SHELL", "curl -fsS http://localhost:8080/health || exit 1"]
       interval: 10s
       timeout: 5s
       retries: 5