traefik/traefik.env did not exist on the host after PR #21 merged. Root
cause: provisioning only renders on a push touching traefik/, and traefik
is bootstrap-tier (stack-deploy.sh runs manually, never via the pipeline).
A manual stack-deploy.sh traefik run apparently happened while the env file
was absent, causing Swarm's own interpolation to render
KEEPALIVED_PASSWORD/KEEPALIVED_VIRTUAL_IPS as empty strings on
keepalived-master. This comment-only change re-triggers provision-secrets;
a manual stack-deploy.sh traefik run is still required afterward to apply
the freshly-rendered env to the running services.