feat: add gated Compose deploy and make inventory the host source of truth

Keep sanitized Compose sources in-repo with a confirmation-gated Ansible
playbook, add repo-wide validation, tighten runbook ownership/STOP/review
metadata, and archive stale research docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

compose/README.md

@@ -0,0 +1,48 @@
+# compose/ — repo-owned Compose declarations
+
+Non-secret Compose sources for the Docker hosts. Secrets are **never** in these
+files: every secret is a `${VAR}` reference resolved from the **server-local
+`.env`** (docker compose reads `.env` from the project directory automatically).
+
+## Source-of-truth matrix
+
+| Project | Host | Compose source | Mechanism |
+|---------|------|----------------|-----------|
+| `vaultwarden` | us2 (`/opt/vaultwarden`) | `compose/vaultwarden/compose.yml` | static file + `compose-deploy.yml` |
+| `pdns` | hk2 (`/opt/pdns`) | `compose/pdns/compose.yml` | static file + `compose-deploy.yml` |
+| `adguardhome` | dns.windy.lan (`/opt/adguardhome`) | — (待从 LAN 提取) | static file (pending) |
+| `unifi` | ubnt (`/home/windy/unifi-9`) | — (待从 LAN 提取) | static file (pending) |
+| `wireguard` | us4 (`/opt/wireguard`) | `ansible/templates/wireguard-compose.yml.j2` | role-rendered (inventory vars) |
+| `rustdesk` | hk2 (`/opt/rustdesk`) | `ansible/roles/rustdesk/templates/compose.yml.j2` | role-rendered (inventory vars) |
+| `mailcow` | mx2 (`/opt/mail`) | — (mailcow update generator owns it) | excluded by design |
+
+Mechanism rule: **static** `compose/<project>/compose.yml` for declarations that
+do not vary per host; **role-rendered j2** for declarations driven by inventory
+vars (image pins, relay host). One mechanism per project; do not duplicate a
+project in both.
+
+## Deploying a static project
+
+```bash
+cd ansible
+
+# Read-only diff + validation against the server .env (no writes)
+ansible-playbook playbooks/compose-deploy.yml --limit vaultwarden --check --diff
+
+# Apply: stage repo file → validate `docker compose config -q` → backup current
+# file → promote → `docker compose up -d` (gated)
+ansible-playbook playbooks/compose-deploy.yml --limit vaultwarden \
+  -e '{"compose_deploy_confirm": true}'
+```
+
+See [`../runbooks/ansible-operations.md`](../runbooks/ansible-operations.md).
+
+## Adding a project
+
+1. Sanitize the live compose so every secret is `${VAR}` from `.env`
+   (prefer `${VAR:?missing VAR}` for required keys).
+2. Commit `compose/<project>/compose.yml` + `.env.example` (key names only).
+3. Add `compose_repo_project` (+ `compose_remote_file` if not `compose.yml`) to
+   the host in `ansible/inventory/hosts.yml`, and allowlist the project in
+   `ansible/roles/compose_deploy/defaults/main.yml`.
+4. Verify with `--check --diff` (zero diff) then a gated apply.