fix: correct real-world deployment details found while writing the stacks entry

- docker-compose.yml used "websecure" as the entrypoint name; the
  actual falcon_network convention (confirmed against the real
  traefik/compose.yml) is "web-secure". Also switched the networks
  block from a hardcoded falcon_network to the same
  compose_network-aliased ${NETWORK_NAME} pattern already used in the
  Traefik labels, instead of only half-respecting that variable.
- config.yml gave the Traefik widget an href, but this deployment runs
  with --api.dashboard=false - there's no dashboard to link to.

config/.env.example

@@ -1,7 +1,6 @@
 # Public hostnames of the services PulseNode links to / monitors.
 # These are not secrets, but keeping them here (rather than hardcoded in
 # config.yml) means the same config.yml works across environments.
-TRAEFIK_HOST_TRAEFIK=traefik.example.com
 TRAEFIK_HOST_CODE=code.example.com
 TRAEFIK_HOST_COOLIFY=coolify.example.com
 TRAEFIK_HOST_GITEA=git.example.com