feat(deploy): Server-Backup und Restore für Produktion

Automatisiert pg_dump, .env, Compose und Git-Archiv mit Tag-Zuordnung, Retention (5) und Pre-Deploy-Hook nur für Prod.

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

README.md

@@ -258,6 +258,8 @@ Standard-Ziel Prod: `root@10.0.0.25:/opt/kapteins-daagbok` — per `REMOTE_HOST`
 
 Auf dem Server müssen `.env` u. a. `POSTGRES_PASSWORD`, `RP_ID`, `ORIGIN` (`https://kapteins-daagbok.eu`), `SESSION_SECRET` (≥ 32 Zeichen), `TRUST_PROXY` (NPM, z. B. `172.16.10.10` oder `1`) und bei Push `VAPID_*` enthalten. Optional `NTFY_*` für Feedback. Nach Schema-Änderungen: `npx prisma db push` im Backend-Container.
 
+Prod-Deploy legt vor dem Update automatisch ein Server-Backup an (DB, `.env`, Compose, App-Code). Tägliches Cron-Backup und Restore: [docs/deployment/backup.md](docs/deployment/backup.md).
+
 Hinter **Nginx Proxy Manager**: [docs/deployment/npm-security.md](docs/deployment/npm-security.md).
 
 ### Staging
@@ -277,6 +279,7 @@ Standard-Ziel Staging: `root@10.0.0.27:/opt/kapteins-daagbok-staging` — per `R
 | [docs/deployment/npm-security.md](docs/deployment/npm-security.md) | NPM, TLS, `trust proxy`, Security-Header |
 | [docs/deployment/predeploy.md](docs/deployment/predeploy.md) | Pre-Deploy-Checks ohne CI |
 | [docs/deployment/postgres-password.md](docs/deployment/postgres-password.md) | PostgreSQL-Passwort rotieren / App-Rolle |
+| [docs/deployment/backup.md](docs/deployment/backup.md) | Server-Backup, Crontab, Restore (Prod) |
 | [docs/deployment/staging.md](docs/deployment/staging.md) | Staging-VM, Deploy, `.env` |
 | [docs/plausible-events.md](docs/plausible-events.md) | Custom Events für Plausible Analytics |
 | [docs/push-notifications-plan.md](docs/push-notifications-plan.md) | Web Push: Architektur, API, Testplan |