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>

deploy.sh

@@ -55,10 +55,13 @@ done
 info "All images built and pushed."
 
 # ── Sync compose file to Unraid ──────────────────────────────────
-info "Copying docker-compose.prod.yml to Unraid..."
+info "Copying docker-compose.prod.yml and backup.sh to Unraid..."
 scp docker-compose.prod.yml "${UNRAID_SSH}:${UNRAID_DEPLOY_DIR}/docker-compose.yml" \
     || error "Failed to copy compose file to Unraid."
-info "Compose file synced."
+scp backup.sh "${UNRAID_SSH}:${UNRAID_DEPLOY_DIR}/backup.sh" \
+    || error "Failed to copy backup script to Unraid."
+ssh "${UNRAID_SSH}" "chmod +x '${UNRAID_DEPLOY_DIR}/backup.sh'"
+info "Compose file and backup script synced."
 
 # ── Ensure .env with Postgres password exists ────────────────────
 info "Checking for .env on Unraid..."
@@ -72,6 +75,18 @@ ssh "${UNRAID_SSH}" "
     fi
 " || error "Failed to check/create .env on Unraid."
 
+# ── Ensure daily backup cron job exists ───────────────────────────
+info "Checking for backup cron job on Unraid..."
+CRON_CMD="0 3 * * * ${UNRAID_DEPLOY_DIR}/backup.sh >> ${UNRAID_DEPLOY_DIR}/backups/cron.log 2>&1"
+ssh "${UNRAID_SSH}" "
+    if ! crontab -l 2>/dev/null | grep -qF '${UNRAID_DEPLOY_DIR}/backup.sh'; then
+        (crontab -l 2>/dev/null; echo '${CRON_CMD}') | crontab -
+        echo 'Cron job installed (daily at 03:00)'
+    else
+        echo 'Cron job already exists, skipping'
+    fi
+" || error "Failed to set up backup cron job on Unraid."
+
 # ── Pull images and (re)start on Unraid ──────────────────────────
 info "Pulling images and starting containers on Unraid..."
 ssh "${UNRAID_SSH}" "cd '${UNRAID_DEPLOY_DIR}' && docker compose pull && docker compose up -d" \