ci: add a spam comment detection

When a comment is added in an issue

1. if the comment has specific words, it will be deleted
2. if the comment has unexpected links, an annotation about
safety will be appended.

.github/workflows/spam-comment-detection.yaml

@@ -0,0 +1,45 @@
+name: Spam detection
+
+on:
+  issue_comment:
+    types: [created, edited]
+
+jobs:
+  detect-spam:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Node.js
+        uses: actions/setup-node@main
+
+      - name: Check for Spam
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const comment = process.env.COMMENT_BODY
+            const spam_words = ['Neuron Support Request']
+            const comment_id = process.env.COMMENT_ID
+            const issue_number = process.env.ISSUE_NUMBER
+            const owner = process.env.REPO_OWNER
+            const repo = process.env.REPO_NAME
+            const EXTERNAL_LINK_REGEXT = /https:\/\/(?!((\w+\.)?github\.com|github\.com|(\w+\.)?magickbase\.com|(\w+\.)?nervos\.org))/gi
+            if (spam_words.some(w => comment.includes(w))) {
+              console.info(`Spam comment: ${comment}`)
+              github.rest.issues.deleteComment({ owner, repo, comment_id })
+            } else if (EXTERNAL_LINK_REGEXT.test(comment)) {
+              console.info(`External link detected, append an annotation`)
+              github.rest.issues.createComment({
+                owner,
+                repo,
+                issue_number,
+                body: `An external link is mentioned in the comment above. Please verify the link's safety before visiting.`
+              })
+            } else {
+              console.info("No spam detected")
+            }
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          COMMENT_BODY: ${{ github.event.comment.body }}
+          COMMENT_ID: ${{ github.event.comment.id }}
+          ISSUE_NUMBER: ${{ github.event.issue.number }}
+          REPO_OWNER: ${{github.repository_owner }}
+          REPO_NAME: ${{ github.event.repository.name }}