fix(flake): make Hetzner the canonical cc-ci host target

docs/install.md

@@ -53,6 +53,7 @@ install -m700 -d /var/lib/sops-nix
 install -m600 /path/to/bootstrap-age-key /var/lib/sops-nix/key.txt
 
 # 3. One nixos-rebuild switch. NOTE: ?submodules=1 so the git flake includes secrets/.
+#    `#cc-ci` is the canonical live Hetzner host target. The old Incus config is `#cc-ci-incus`.
 nixos-rebuild switch --flake 'git+file:///root/cc-ci?submodules=1#cc-ci'
 ```