Add stop.sh (compose down) and disable print_forge (#34)

## Summary
- Closes [#33](#33).
- Add `scripts/stop.sh` → `playbooks/stop-apps.yml` → `docker compose down` for one `--app` + `--env` (no `-v`; checkouts/secrets stay).
- `host_apps.enabled: false` skips deploy (including CI `--app`) so a stopped app cannot come back. Rows stay for ports and `stop.sh`.
- Disable `print_forge` beta + prod on all app hosts. After merge (or from this branch): `./scripts/stop.sh --app print_forge --env prod` and `--env beta`.

## Test plan
- [ ] `./scripts/stop.sh --help` shows required `--app` / `--env`
- [ ] `ansible-playbook playbooks/stop-apps.yml --syntax-check -e app=print_forge -e app_env=prod`
- [ ] `./scripts/stop.sh --app print_forge --env prod` compose-downs `print_forge_prod` on all webservers
- [ ] `./scripts/stop.sh --app print_forge --env beta` compose-downs `print_forge_beta` (including adama worker)
- [ ] `./scripts/deploy.sh --app print_forge --env prod --check` skips disabled rows (does not start containers)
- [ ] NPM: `print-forge-preview.aimloperations.com` will 502 until the proxy host is disabled (out of scope)

Reviewed-on: #34

playbooks/stop-apps.yml

@@ -0,0 +1,15 @@
+---
+# Stop one docker-compose app+env. Inverse of deploy-apps.yml start.
+#
+#   ansible-playbook playbooks/stop-apps.yml -e app=print_forge -e app_env=prod
+#
+# host_apps rows with enabled: false are still valid stop targets (so a
+# disabled app can be taken down). Node-static apps are skipped.
+- name: Stop applications
+  hosts: webservers
+  become: true
+  tasks:
+    - name: Stop requested compose apps
+      ansible.builtin.include_role:
+        name: app-deploy
+        tasks_from: stop.yml