fix: add Docker Compose V2 support for all management scripts

Add docker-compose-helper.sh to auto-detect and use:
- docker-compose (V1 - standalone)
- docker compose (V2 - plugin)

Update all 9 management scripts to use the helper:
- start.sh, stop.sh, restart.sh
- logs.sh, status.sh
- backup.sh, restore.sh, update.sh, cleanup.sh

This fixes "docker-compose: command not found" error on systems
with Docker Compose V2 installed.

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

docker-compose-helper.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+# Docker Compose 輔助函數
+# 自動檢測使用 docker-compose 或 docker compose
+
+# 檢測並設定 docker compose 命令
+DOCKER_COMPOSE_CMD=""
+
+if command -v docker-compose &> /dev/null; then
+    # Docker Compose V1 (獨立命令)
+    DOCKER_COMPOSE_CMD="docker-compose"
+elif docker compose version &> /dev/null 2>&1; then
+    # Docker Compose V2 (docker plugin)
+    DOCKER_COMPOSE_CMD="docker compose"
+else
+    echo "❌ 找不到 Docker Compose"
+    echo "請安裝 Docker Compose："
+    echo "  V1: https://docs.docker.com/compose/install/"
+    echo "  V2: 已包含在 Docker Desktop 中"
+    exit 1
+fi
+
+# 執行 docker compose 命令的函數
+docker_compose() {
+    $DOCKER_COMPOSE_CMD "$@"
+}