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

docs/install-ubuntu-24.04-docker.md

@@ -0,0 +1,105 @@
+# Ubuntu 24.04 — установка SAC (Docker Compose)
+
+**Альтернативный** способ. В KalinaMall для production используется **[native](install-ubuntu-24.04-native.md)**.
+
+Docker удобен для локальной отладки или изолированного стенда.
+
+---
+
+## 0. Исходные данные
+
+| Параметр | Пример |
+|----------|--------|
+| Каталог | `/opt/security-alert-center` |
+
+---
+
+## 1. Базовая ОС и ufw
+
+Как в [native-руководстве](install-ubuntu-24.04-native.md) §1 (без PostgreSQL/nginx на хосте, если всё в контейнерах — nginx можно на хосте для TLS).
+
+---
+
+## 2. Git и клон
+
+```bash
+sudo apt install -y git
+sudo git clone https://git.kalinamall.ru/PapaTramp/security-alert-center.git /opt/security-alert-center
+sudo chown -R "$USER:$USER" /opt/security-alert-center
+```
+
+---
+
+## 3. Docker Engine + Compose
+
+```bash
+sudo apt install -y ca-certificates curl gnupg
+sudo install -m 0755 -d /etc/apt/keyrings
+curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
+sudo chmod a+r /etc/apt/keyrings/docker.gpg
+
+echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu noble stable" | \
+  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
+
+sudo apt update
+sudo apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin
+sudo usermod -aG docker "$USER"
+# перелогиниться
+docker compose version
+```
+
+---
+
+## 4. Конфигурация
+
+```bash
+sudo mkdir -p /etc/security-alert-center
+cp /opt/security-alert-center/deploy/.env.example /etc/security-alert-center/.env
+chmod 600 /etc/security-alert-center/.env
+nano /etc/security-alert-center/.env
+ln -sf /etc/security-alert-center/.env /opt/security-alert-center/deploy/.env
+```
+
+Заполнить: `POSTGRES_PASSWORD`, `JWT_SECRET`, `SAC_PUBLIC_URL`, `SAC_BOOTSTRAP_API_KEY`.
+
+---
+
+## 5. Запуск
+
+```bash
+cd /opt/security-alert-center/deploy
+docker compose up -d --build
+docker compose run --rm migrate
+docker compose ps
+curl -sS http://127.0.0.1:8000/health
+```
+
+---
+
+## 6. Бэкап (Docker)
+
+```bash
+sudo tee /etc/cron.d/sac-backup <<'EOF'
+0 3 * * * root docker compose -f /opt/security-alert-center/deploy/docker-compose.yml exec -T postgres pg_dump -U sac -Fc sac > /var/backups/sac/sac_$(date +\%Y\%m\%d).dump
+EOF
+```
+
+---
+
+## 7. Обновление
+
+```bash
+cd /opt/security-alert-center
+git pull
+cd deploy
+docker compose build
+docker compose up -d
+docker compose run --rm migrate
+```
+
+---
+
+## См. также
+
+- [install-ubuntu-24.04-native.md](install-ubuntu-24.04-native.md) — основной путь
+- [../deploy/docker-compose.yml](../deploy/docker-compose.yml)