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>

start.sh

@@ -3,7 +3,12 @@
 
 set -e
 
+# 載入 docker compose 輔助函數
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/docker-compose-helper.sh"
+
 echo "🚀 啟動 CodiMD 服務..."
+echo "   使用: $DOCKER_COMPOSE_CMD"
 
 # 檢查 .env 是否存在
 if [ ! -f .env ]; then
@@ -23,7 +28,7 @@ if ! docker info > /dev/null 2>&1; then
 fi
 
 # 啟動服務
-docker-compose up -d
+docker_compose up -d
 
 echo ""
 echo "⏳ 等待服務啟動..."
@@ -32,7 +37,7 @@ sleep 5
 # 顯示服務狀態
 echo ""
 echo "📊 服務狀態："
-docker-compose ps
+docker_compose ps
 
 echo ""
 echo "✅ CodiMD 已啟動！"