deck-lovers: the deploy script checks host ports before it builds

Podman only reports a host-port clash after the images are built, and only as an opaque “proxy already running” error that never names the port. The deploy script in deck-lovers now runs a pre-flight check in local serve mode before the build, naming the container or host process that is actually holding the port — 80 and 443 included when Caddy is started — while skipping this compose project’s own containers, so re-running over a live deck-lovers server still attaches instead of failing (5c07394).