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

inventory/host_vars/ai-server-4080.yml

@@ -43,8 +43,8 @@ host_apps:
   - { name: url_shortening_service, env: beta, port: 8015 }
   - { name: college_craft, env: prod, port: 8006 }
   - { name: college_craft, env: beta, port: 8016 }
-  - { name: print_forge, env: prod, port: 8007 }
-  - { name: print_forge, env: beta, port: 8019 }
+  - { name: print_forge, env: prod, port: 8007, enabled: false }
+  - { name: print_forge, env: beta, port: 8019, enabled: false }
   - { name: abc_be, env: beta, port: 8017 }
   - { name: abc_worker, env: beta, port: 8018 }
   - { name: abc_fe, env: beta, port: 8085 }