ci(deploy): pull the prebuilt published image in prod instead of building on host

The prod compose api service now references the published Forgejo image
(tag = released VERSION) and deploy.sh pulls it rather than running a host
build. The image carries its baked-in version/sha/build-date from publish.

docker-compose.prod.yml

@@ -34,14 +34,10 @@ services:
     restart: unless-stopped
 
   api:
-    build:
-      context: .
-      dockerfile: Dockerfile
-      args:
-        APP_VERSION: ${APP_VERSION:-dev}
-        GIT_SHA: ${GIT_SHA:-unknown}
-        BUILD_DATE: ${BUILD_DATE:-}
-    image: siftlode-api:local
+    # Prod pulls the prebuilt image published by `siftlode publish` instead of building on
+    # the host. The tag follows the released VERSION (deploy.sh exports APP_VERSION); the
+    # image already carries the baked-in version/sha/build-date stamps from the publish build.
+    image: forge.b1fr0st.eu/peter/siftlode:${APP_VERSION:-latest}
     env_file:
       - /srv/siftlode/.env
     environment: