Internal downstream skill for ctf-sandbox-orchestrator. CTF-sandbox workflow for reverse proxies, Host headers, forwarded headers, vhost routing, websocket upgrades, path-prefix rewriting, base-URL derivation, and multi-node route resolution. Use when the user asks which host or container serves a route, why a public-looking domain still belongs to the sandbox, how headers or proxies change behavior, or how a route resolves across proxy, container, and worker boundaries. Use only after `$ctf-sandbox-orchestrator` has already established sandbox assumptions and routed here.