chore(docker): ensure resilient multi-arch detection and explicit ziglang dependency

docker-compose.yml

@@ -1,7 +1,7 @@
 # SCOPENET admin panel
 #
 #   cp .env.example .env    # set ADMIN_PASSWORD at least
-#   docker compose up -d
+#   docker compose up -d --build
 #
 # Then open http://localhost:8080 (or your domain behind a reverse proxy).
 services: