Add GitHub workflow for MDX format checking and fix parsing error (#10924)

Co-authored-by: openhands <openhands@all-hands.dev>

.github/workflows/mdx-lint.yml

@@ -0,0 +1,70 @@
+# Workflow that checks MDX format in docs/ folder
+name: MDX Lint
+
+# Run on pushes to main and on pull requests that modify docs/ files
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'docs/**/*.mdx'
+  pull_request:
+    paths:
+      - 'docs/**/*.mdx'
+
+# If triggered by a PR, it will be in the same group. However, each commit on main will be in its own unique group
+concurrency:
+  group: ${{ github.workflow }}-${{ (github.head_ref && github.ref) || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  mdx-lint:
+    name: Lint MDX files
+    runs-on: blacksmith-4vcpu-ubuntu-2204
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Node.js 22
+        uses: useblacksmith/setup-node@v5
+        with:
+          node-version: 22
+
+      - name: Install MDX dependencies
+        run: |
+          npm install @mdx-js/mdx@3 glob@10
+
+      - name: Validate MDX files
+        run: |
+          node -e "
+          const {compile} = require('@mdx-js/mdx');
+          const fs = require('fs');
+          const path = require('path');
+          const glob = require('glob');
+
+          async function validateMDXFiles() {
+            const files = glob.sync('docs/**/*.mdx');
+            console.log('Found', files.length, 'MDX files to validate');
+
+            let hasErrors = false;
+
+            for (const file of files) {
+              try {
+                const content = fs.readFileSync(file, 'utf8');
+                await compile(content);
+                console.log('✅ MDX parsing successful for', file);
+              } catch (err) {
+                console.error('❌ MDX parsing failed for', file, ':', err.message);
+                hasErrors = true;
+              }
+            }
+
+            if (hasErrors) {
+              console.error('\\n❌ Some MDX files have parsing errors. Please fix them before merging.');
+              process.exit(1);
+            } else {
+              console.log('\\n✅ All MDX files are valid!');
+            }
+          }
+
+          validateMDXFiles();
+          "