ci: 修复并增强 GitHub Actions workflow

- 添加脚本可执行权限 (chmod +x)
- 添加并发控制避免重复运行
- 添加 npm 缓存加速构建
- 优化步骤命名
- 添加文件权限检查步骤

Author: shijiashuai

.github/workflows/validate.yml

@@ -6,18 +6,32 @@ on:
   pull_request:
     branches: [master, main]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   validate:
+    name: Validate MDC Files
     runs-on: ubuntu-latest
-    
+
     steps:
-      - name: Checkout code
+      - name: Checkout repository
         uses: actions/checkout@v4
-        
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
           node-version: '20'
-          
-      - name: Validate rule files
+          cache: 'npm'
+
+      - name: Validate MDC rule files
         run: node scripts/validate-rules.mjs
+
+      - name: Check file permissions
+        run: |
+          if [ -x scripts/validate-rules.mjs ]; then
+            echo "✅ Script has executable permission"
+          else
+            echo "⚠️ Script missing executable permission"
+          fi