feat: Add workflow to require closing keywords on PRs

.github/workflows/require-issue-link.yml

@@ -0,0 +1,21 @@
+name: Require Closing Keyword
+
+on:
+  pull_request:
+    branches:
+      - master
+    types: [opened, edited, synchronize, reopened]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Ensure PR closes an issue
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const body = context.payload.pull_request.body || '';
+            const keywordPattern = /(close[sd]?|fix(e[sd])?|resolve[sd]?)\s+((#[0-9]+)|([\w.-]+\/[\w.-]+#\d+))/i;
+            if (!keywordPattern.test(body)) {
+              core.setFailed('Add a closing keyword like "Closes #123" to the PR description.');
+            }