compose: Traefik label-based auto-discovery

Add Traefik labels so the Docker provider auto-discovers the app.
Includes traefik.docker.network (the app is on two networks) which is
the usual fix for routing not resolving. Host/entrypoint/certresolver
overridable via PRINTHIVE_HOST / TRAEFIK_ENTRYPOINT / TRAEFIK_CERTRESOLVER.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.yml

@@ -19,6 +19,7 @@ services:
     #   docker build -t git.plexultra.com/dlawler489/printhive:latest .
     image: git.plexultra.com/dlawler489/printhive:latest
     pull_policy: always
+    container_name: printhive-app   # stable name for the Traefik file-provider to target
     depends_on:
       db:
         condition: service_healthy
@@ -34,19 +35,30 @@ services:
       - uploads:/app/uploads
       - thumbnails:/app/thumbnails
       - glb:/app/glb
-    ports:
-      - "3000:3000"
+    # No host port published — Traefik auto-discovers the app on the shared network.
+    networks:
+      - default     # talk to the db
+      - traefik     # reachable by Traefik
     restart: unless-stopped
-    # Traefik (if using labels rather than your file provider):
-    # labels:
-    #   - "traefik.enable=true"
-    #   - "traefik.http.routers.printhive.rule=Host(`printhive.plexultra.com`)"
-    #   - "traefik.http.routers.printhive.entrypoints=websecure"
-    #   - "traefik.http.routers.printhive.tls.certresolver=letsencrypt"
-    #   - "traefik.http.services.printhive.loadbalancer.server.port=3000"
+    labels:
+      - "traefik.enable=true"
+      # App is on two networks; tell Traefik which one to reach it on.
+      - "traefik.docker.network=${TRAEFIK_NETWORK:-traefik}"
+      - "traefik.http.routers.printhive.rule=Host(`${PRINTHIVE_HOST:-printhive.plexultra.com}`)"
+      - "traefik.http.routers.printhive.entrypoints=${TRAEFIK_ENTRYPOINT:-websecure}"
+      - "traefik.http.routers.printhive.tls.certresolver=${TRAEFIK_CERTRESOLVER:-letsencrypt}"
+      - "traefik.http.services.printhive.loadbalancer.server.port=3000"
 
 volumes:
   pgdata:
   uploads:
   thumbnails:
   glb:
+
+networks:
+  default:
+  # The existing Traefik network (same one your other services use).
+  # Set TRAEFIK_NETWORK in Dockhand to its exact name.
+  traefik:
+    external: true
+    name: ${TRAEFIK_NETWORK:-traefik}