feat: add FastAPI manager API compatibility baseline

main/manager-api-fastapi/deploy/nginx-entrypoint.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -eu
+
+UPSTREAM=${MANAGER_API_UPSTREAM:-manager-api-fastapi:8002}
+case "${UPSTREAM}" in
+  ''|*[!A-Za-z0-9._:-]*)
+    echo "MANAGER_API_UPSTREAM must be a hostname-or-IP and port" >&2
+    exit 2
+    ;;
+esac
+
+export MANAGER_API_UPSTREAM=${UPSTREAM}
+envsubst '${MANAGER_API_UPSTREAM}' \
+  < /etc/nginx/nginx.conf.template \
+  > /tmp/manager-api-nginx.conf
+exec nginx -c /tmp/manager-api-nginx.conf -g 'daemon off;'