PR#2 of the AWS migration. deploy/ami/: Packer template (Ubuntu 24.04 arm64,
uv+py3.12, nginx, awscli v2, CW agent; no swapfile), provisioning-only user-data
(userDataCausesReplacement rationale), systemd unit + nginx + CW templates.
Incorporates T5 /sh-security-review fixes: langgraph binds 127.0.0.1 (not 0.0.0.0);
nginx is the sole ingress proxying only /dashboard/api/ + /webhooks/; ExecStartPre
runs fetch-config as root (+) and passes the env arg; the app runs as the
unprivileged openswe user reading an openswe-owned 0600 .env. packer validate clean.
