Fix Traefik SSL certificate issues

- Fixed volume mount syntax for Swarm (use long-form bind mount syntax)
- Fixed Portainer TLS label syntax (tls.certresolver instead of tls.certificatesResolvers)
- These changes resolve SSL errors and certificate mounting issues

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stacks/core/portainer/stack.yml

@@ -14,9 +14,11 @@ services:
       labels:
       - "traefik.enable=true"
       - "traefik.swarm.network=homelab"
+      # Public-facing domain with Let's Encrypt certificate
       - "traefik.http.routers.portainer.rule=Host(`portainer.frostlabs.me`)"
       - "traefik.http.routers.portainer.entrypoints=websecure"
-      - "traefik.http.routers.portainer.tls.certificatesResolvers=cloudflare"
+      - "traefik.http.routers.portainer.tls=true"
+      - "traefik.http.routers.portainer.tls.certresolver=cloudflare"
       - "traefik.http.services.portainer.loadbalancer.server.port=9000"
 
   agent: