docs: native Ubuntu install as primary; systemd and nginx

- install-ubuntu-24.04-native.md (production) and -docker.md (alternative)

- deploy/systemd/sac-api.service, nginx/sac.conf.example, env.native.example

- deployment, README, INDEX, work-plan, TZ updated

deploy/README.md

@@ -1,10 +1,18 @@
 # Deploy
 
+## Production (native) — основной путь
+
+1. [docs/install-ubuntu-24.04-native.md](../docs/install-ubuntu-24.04-native.md)
+2. `deploy/env.native.example` → `/etc/security-alert-center/sac-api.env`
+3. `deploy/systemd/sac-api.service` → `/etc/systemd/system/`
+4. `deploy/nginx/sac.conf.example` → `/etc/nginx/sites-available/sac`
+
+## Альтернатива: Docker
+
+Только для стенда. См. [docs/install-ubuntu-24.04-docker.md](../docs/install-ubuntu-24.04-docker.md).
+
 ```bash
-cp .env.example .env
-nano .env
+cp .env.example .env   # docker-only
 docker compose up -d --build
 docker compose run --rm migrate
 ```
-
-Полная инструкция для Ubuntu 24.04: [../docs/install-ubuntu-24.04.md](../docs/install-ubuntu-24.04.md)