p5-07: reference deployment (server-only compose + reverse-proxy docs)

The reverse proxy is assumed to live outside this project (Caddy,
nginx, Traefik, whatever the operator already runs). The reference
compose stands up only the server: image-pinned via RM_VERSION,
named volume for operator state, localhost-bound so the proxy
reaches it on loopback.

docs/reverse-proxy.md covers what the proxy must forward — the
X-Forwarded-* headers, Host, and Connection: upgrade for the agent
WebSocket and live-log streams — plus the RM_TRUSTED_PROXY CIDR
rule that gates header trust. Worked examples for Caddy, nginx
(with the websocket upgrade map + 1h proxy_read_timeout for live
logs), and Traefik.

tasks.md

@@ -332,7 +332,7 @@ Sizes: **S** = under a day, **M** = 1–3 days, **L** = 3–7 days.
 - [ ] **P5-04** (S) Demo screenshots / short Loom walkthrough in README
 - [ ] **P5-05** (S) `SECURITY.md` with disclosure process
 - [ ] **P5-06** (M) End-to-end test suite in CI (Playwright vs. compose stack with sibling Linux agent)
-- [ ] **P5-07** (S) Reference deployment: `docker-compose.yml` + Caddyfile snippet showing the TLS-terminating reverse proxy in front of the HTTP-only server (also demonstrates `RM_TRUSTED_PROXY`)
+- [x] **P5-07** (S) Reference deployment landed alongside P5-03. `deploy/docker-compose.yml` stands up *only* the server (image-pinned via `RM_VERSION`, named volume for operator state, bound to localhost) — TLS termination is left to whichever reverse proxy the operator already runs. `docs/reverse-proxy.md` documents the headers + WebSocket pass-through the proxy must forward, the `RM_TRUSTED_PROXY` CIDR rule, and worked examples for Caddy, nginx, and Traefik.
 
 ### Phase 5 acceptance