fix: schedule weekly full postgres backup

infra/postgres-backup.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+set -eu
+umask 077
+
+app_dir=/srv/miem_workers
+backup_dir=/home/codex/backups/postgres
+backup="$backup_dir/postgres-latest.sql"
+temporary="$backup.tmp.$$"
+
+mkdir -p "$backup_dir"
+trap 'rm -f -- "$temporary"' EXIT HUP INT TERM
+cd "$app_dir"
+
+docker compose exec -T postgres sh -c 'pg_dumpall -U "$POSTGRES_USER"' > "$temporary"
+test -s "$temporary"
+mv "$temporary" "$backup"
+find /home/codex/backups/miem_workers -maxdepth 1 -type f -name 'miem_workers-*.sql' -delete 2>/dev/null || true
+printf '%s\n' "Created $backup"