DokPloy's redeploy process rm -rf's the host code dir and recreates it.
The cron container is `restart: unless-stopped` so docker-compose
doesn't recreate it when only scripts/* change — but its bind mount on
./scripts:/app/scripts then points at orphaned inodes inside the
running container, leaving /app/scripts empty until someone manually
`docker restart`s it.
Bake the scripts into the image instead. A scripts/* change now forces
a Dockerfile rebuild → docker-compose recreates the cron service →
fresh /app/scripts inside, no manual restart required. content/ and
.git/ stay bind-mounted because the export job needs to write commits
the host can see.
Also adds .dockerignore so the host's scripts/node_modules (potentially
darwin-specific) doesn't get COPY'd into the alpine image and shadow
the deps installed by `npm install` at build time.
