Two features built this session, committed together as a checkpoint before the
deployment-model refactor (they share files, so kept as one rollback point):
- Public exposure via Cloudflare tunnel: a `public` toggle on services (requires
proxy), gateway.public_domain/tunnel_id config, a cloudflared ingress generator
(generators/tunnel.py) that maps <name>.<public_domain> to the gateway's
internal host, deploy wiring, and docs/tunnel-setup.md.
- Frontends as `static`-runner services: a RunStatic runner served by Caddy
(file_server), no systemd unit (like `remote`); the Caddyfile generator now
derives static routes from services instead of a behavior==frontend branch.
