refactor(hindsight): 使用Volumes_Path替代硬编码路径

- backup.job 改为从 env.cfg 读取 Volumes_Path
- stack.yml 路径替换为变量引用
- .gitignore 添加 hindsight/env.cfg

hindsight/backup.job

@@ -6,7 +6,11 @@
 # ============================================================
 set -euo pipefail
 
-BACKUP_DIR="/home/geng/hindsight/backups"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=/dev/null
+source "${SCRIPT_DIR}/env.cfg"
+
+BACKUP_DIR="${Volumes_Path}/backups"
 KEEP_DAYS=7
 TS=$(date +%Y%m%d_%H%M%S)
 FNAME="hindsight_db_${TS}.sql.gz"