Add database backup script with daily cron and 7-day retention

pg_dump-based backup script deployed alongside compose file. Deploy
script now installs a daily cron job (03:00) on Unraid automatically.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.beans/nuzlocke-tracker-48ds--database-backup-strategy.md

@@ -1,10 +1,11 @@
 ---
 # nuzlocke-tracker-48ds
 title: Database backup strategy
-status: todo
+status: completed
 type: task
+priority: normal
 created_at: 2026-02-09T15:30:55Z
-updated_at: 2026-02-09T15:30:55Z
+updated_at: 2026-02-10T10:55:15Z
 parent: nuzlocke-tracker-ahza
 ---
 

.beans/nuzlocke-tracker-ahza--deployment-strategy.md

@@ -54,5 +54,5 @@ Define and implement a deployment strategy for running the nuzlocke-tracker in p
 - [x] **Configure Nginx Proxy Manager** — add proxy host entries for Gitea and the nuzlocke-tracker frontend/API on the appropriate ports
 - [x] **Environment & secrets management** — deploy script auto-generates `.env` with `POSTGRES_PASSWORD` on Unraid if missing; file lives at `/mnt/user/appdata/nuzlocke-tracker/.env`
 - [ ] **Implement Gitea Actions CI/CD pipeline** — set up Gitea Actions runner on Unraid, create CI workflow (lint/test on `develop`) and deploy workflow (build/push/deploy on `main`); uses GitHub Actions-compatible syntax for portability
-- [ ] **Database backup strategy** — set up a simple scheduled backup for the PostgreSQL data (e.g., cron + `pg_dump` script on Unraid)
+- [x] **Database backup strategy** — set up a simple scheduled backup for the PostgreSQL data (e.g., cron + `pg_dump` script on Unraid)
 - [ ] **Document the deployment workflow** — README or docs covering how to deploy, redeploy, rollback, and manage the production instance