[FIX] 修復 CI/CD 部署時序競爭 - 容器重啟導致 docker exec 隨機失敗

根因：queue/mqtt-worker 容器可能處於 restarting 狀態，
docker exec 在此狀態下會被拒絕 (exit 1)，導致部署隨機失敗。

修復：在 deploy_to 函式中加入 wait_for_container 重試邏輯，
在執行 docker exec 前先等待容器進入 running 狀態 (最多 30 秒)。

.gitea/workflows/deploy-demo.yaml

@@ -42,9 +42,31 @@ jobs:
       - name: Step 2 - Deploy Code
         shell: bash
         run: |
+          # 等待容器進入 running 狀態 (最多 30 秒)
+          wait_for_container() {
+            local container=$1
+            local max_attempts=15
+            local attempt=0
+            while [ $attempt -lt $max_attempts ]; do
+              local state=$(docker inspect --format='{{.State.Status}}' "$container" 2>/dev/null)
+              if [ "$state" = "running" ]; then
+                return 0
+              fi
+              attempt=$((attempt + 1))
+              echo "    Waiting for $container (state=$state, attempt $attempt/$max_attempts)..."
+              sleep 2
+            done
+            echo "!!! Error: $container did not reach running state (last state=$state)"
+            return 1
+          }
+
           deploy_to() {
             local container=$1
             echo ">>> Syncing code to $container..."
+
+            # 先確認容器已就緒，避免 restarting 狀態下 docker exec 被拒絕
+            wait_for_container "$container" || return 1
+
             tar --exclude='.git' --exclude='node_modules' --exclude='vendor' --exclude='storage' --exclude='bootstrap/cache' -cf - . \
               | docker exec -i "$container" tar -xf - -C /var/www/html/