M1: proxy via real coop-cloud/traefik (abra, wildcard/no-ACME); recipe deploy+teardown; M1 CLAIMED

Orchestrator decision: deploy canonical coop-cloud traefik via abra instead of a
hand-rolled module. abra packaged in Nix (pinned). custom-html deployed over HTTPS
(200) via the gateway and torn down clean. docs/install.md seeded.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/install.md

@@ -0,0 +1,54 @@
+# Installing cc-ci from scratch
+
+> WORK IN PROGRESS — grows with each milestone; the full from-scratch rebuild is verified at M9 (D8).
+
+cc-ci is declared as a NixOS flake (this repo) plus a reproducible proxy-deploy step. Target:
+a NixOS 24.11 host reachable as `cc-ci` over SSH (root), with the operator preconditions in place.
+
+## Operator preconditions (class-A1, see DECISIONS.md / docs/baseline.md)
+
+- Wildcard TLS cert at `/var/lib/ci-certs/live/{fullchain.pem,privkey.pem}`
+  (`*.ci.commoninternet.net` + `ci.commoninternet.net`). **Renewed out-of-band; never ACME here.**
+- DNS: `*.ci.commoninternet.net` (+ bare) → the **gateway**, which TLS-passthroughs (SNI) to cc-ci.
+- Firewall path: gateway reaches cc-ci on tcp/80+443 (opened by `modules/swarm.nix`).
+
+## 1. Apply the NixOS flake
+
+The flake (`flake.nix`, `hosts/cc-ci/`, `modules/`) declares: base host, sops-nix (decrypts via the
+host SSH key), Docker + single-node Swarm + the `proxy` overlay (`modules/swarm.nix`), and abra
+(`modules/abra.nix`).
+
+```sh
+# materialise the repo on the host (the build runs on cc-ci itself — see DECISIONS.md deploy mech)
+#   e.g. git clone <repo> /root/cc-ci   (or sync it)
+nixos-rebuild switch --flake /root/cc-ci#cc-ci
+# verify
+systemctl is-system-running          # -> running
+docker info --format '{{.Swarm.LocalNodeState}}'   # -> active
+docker network ls | grep proxy       # -> proxy ... overlay swarm
+```
+
+> Tip: when driving the switch over an SSH session that rides Tailscale, run it as a detached unit so
+> it survives a momentary drop, and **use the absolute flake path** (systemd units run with cwd `/`):
+> `systemd-run --unit=ccci-sw --property=Type=oneshot nixos-rebuild switch --flake /root/cc-ci#cc-ci`
+
+## 2. Deploy the reverse proxy (coop-cloud traefik, wildcard/file-provider, no ACME)
+
+```sh
+bash /root/cc-ci/scripts/deploy-proxy.sh
+```
+
+This idempotently deploys the canonical Co-op Cloud `traefik` recipe via abra in wildcard mode,
+serving the pre-issued cert as the `ssl_cert`/`ssl_key` swarm secrets, with `LETS_ENCRYPT_ENV` empty
+so no ACME ever runs (see DECISIONS.md "Proxy: real coop-cloud/traefik via abra"). Verify:
+
+```sh
+docker service ls | grep traefik     # app + socket-proxy, 1/1
+# wildcard cert served end-to-end via the gateway:
+curl -ksv --resolve probe.ci.commoninternet.net:443:<gateway-ip> https://probe.ci.commoninternet.net/ \
+  2>&1 | grep -E 'subject:|HTTP/'    # -> CN=*.ci.commoninternet.net, HTTP 404 (no app router yet)
+```
+
+## 3. (later milestones) Drone, comment-bridge, dashboard, recipe enrollment
+
+See `docs/enroll-recipe.md` (D5), `docs/secrets.md` (D6), `docs/runbook.md`. Added as those land.