DONE: fix error on nginx, add version on env, enable impersonate on staging

docker-compose.staging.yml

@@ -1,23 +1,8 @@
-# Staging stack — isolated from local docker-compose.yml (8081 / 3307)
-# and from api_arrahn staging (8090 / 3308).
-#
-# Local:
-#   docker compose --env-file .env.staging -f docker-compose.staging.yml up -d --build
-#
-# CI (image already in registry):
-#   APP_IMAGE=git.koppkb.com/kopkb/kaunter IMAGE_TAG=<sha> \
-#     docker compose --env-file .env.staging -f docker-compose.staging.yml up -d --no-build
-#
-# Host nginx reverse-proxies the public domain to 127.0.0.1:${HTTP_PORT}.
-# See docker/nginx/host-proxy.example.conf
-#
-# If 8091 or 3309 is already taken, set HTTP_PORT / MYSQL_PUBLISH_PORT in .env.staging.
-
 name: kaunter_staging
 
 services:
   app:
-    image: ${APP_IMAGE:-kaunter}:${IMAGE_TAG:-staging}
+    image: ${APP_IMAGE:-git.koppkb.com/kopkb/kaunter}:${IMAGE_TAG:-staging}
     build:
       context: .
       dockerfile: docker/php/Dockerfile