fix(mirror): Docker proxy port is 5000 not 8083 (matches Nexus httpPort config)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.mirror.yml

@@ -9,7 +9,7 @@
 #   UI     →  http://SERVER_IP:8081       (admin / see provision.sh output)
 #   NuGet  →  http://SERVER_IP:8081/repository/nuget-proxy/index.json
 #   npm    →  http://SERVER_IP:8081/repository/npm-proxy/
-#   Docker →  http://SERVER_IP:8083       (add to /etc/docker/daemon.json)
+#   Docker →  http://SERVER_IP:5000        (add to /etc/docker/daemon.json)
 #
 # Memory: needs ~2 GB JVM heap — recommended on a server with 4 GB+ total RAM.
 # Adjust INSTALL4J_ADD_VM_PARAMS below if your server has more/less RAM.
@@ -30,7 +30,7 @@ services:
       - nexus-data:/nexus-data
     ports:
       - "8081:8081"   # Web UI + NuGet + npm REST API
-      - "8083:8083"   # Docker Hub pull-through proxy (dedicated port required by Docker protocol)
+      - "5000:5000"   # Docker Hub pull-through proxy (httpPort configured in docker-hub-proxy repo)
     healthcheck:
       test: ["CMD", "curl", "-sf", "http://localhost:8081/service/rest/v1/status"]
       interval: 30s