ci: add sample sync check workflow (#13203)

ci: add workflow to check HTML and React sample sync

Adds a GitHub Actions workflow that runs on PRs touching website
samples and comments when HTML or React samples are changed without
updating the other, reminding authors to keep both in sync.

Author: ilhan007

.github/workflows/check-react-samples.yaml

@@ -0,0 +1,104 @@
+name: Check React Samples Sync
+
+on:
+  pull_request:
+    paths:
+      - 'packages/website/docs/_samples/**/sample.html'
+      - 'packages/website/docs/_samples/**/main.js'
+      - 'packages/website/docs/_samples/**/main.css'
+      - 'packages/website/docs/_samples/**/sample.tsx'
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Check sample sync
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const { data: files } = await github.rest.pulls.listFiles({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.issue.number,
+              per_page: 300,
+            });
+
+            const samplesDir = 'packages/website/docs/_samples/';
+            const htmlSampleDirs = new Set();
+            const reactSampleDirs = new Set();
+
+            for (const file of files) {
+              if (!file.filename.startsWith(samplesDir)) continue;
+
+              const rel = file.filename.slice(samplesDir.length);
+              const dir = rel.substring(0, rel.lastIndexOf('/'));
+
+              if (rel.endsWith('/sample.html') || rel.endsWith('/main.js') || rel.endsWith('/main.css')) {
+                htmlSampleDirs.add(dir);
+              }
+              if (rel.endsWith('/sample.tsx')) {
+                reactSampleDirs.add(dir);
+              }
+            }
+
+            const htmlOnly = [...htmlSampleDirs].filter(dir => !reactSampleDirs.has(dir)).sort();
+            const reactOnly = [...reactSampleDirs].filter(dir => !htmlSampleDirs.has(dir)).sort();
+
+            if (htmlOnly.length === 0 && reactOnly.length === 0) {
+              console.log('All changed samples are in sync.');
+              return;
+            }
+
+            const sections = ['### Sample sync reminder', ''];
+
+            if (htmlOnly.length > 0) {
+              sections.push(
+                'HTML sample changed but **React sample** (`sample.tsx`) not updated:',
+                '',
+                ...htmlOnly.map(dir => `- \`${dir}\``),
+                '',
+              );
+            }
+
+            if (reactOnly.length > 0) {
+              sections.push(
+                'React sample changed but **HTML sample** (`sample.html`/`main.js`/`main.css`) not updated:',
+                '',
+                ...reactOnly.map(dir => `- \`${dir}\``),
+                '',
+              );
+            }
+
+            sections.push('Please keep both samples in sync, or ignore if the change does not apply to both.');
+            const body = sections.join('\n');
+
+            // Check for existing comment to avoid duplicates
+            const marker = 'Sample sync reminder';
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+            });
+            const existing = comments.find(c =>
+              c.user.type === 'Bot' && c.body.includes(marker)
+            );
+
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existing.id,
+                body,
+              });
+            } else {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body,
+              });
+            }