[workflows] Refactor auto-label-pr script into modular JS (#13582)

.github/scripts/auto-label-pr/labels.js

@@ -0,0 +1,41 @@
+// Apply labels to PR
+async function applyLabels(github, context, finalLabels) {
+  const { owner, repo } = context.repo;
+  const pr_number = context.issue.number;
+
+  if (finalLabels.length > 0) {
+    console.log(`Adding labels: ${finalLabels.join(', ')}`);
+    await github.rest.issues.addLabels({
+      owner,
+      repo,
+      issue_number: pr_number,
+      labels: finalLabels
+    });
+  }
+}
+
+// Remove old managed labels
+async function removeOldLabels(github, context, managedLabels, finalLabels) {
+  const { owner, repo } = context.repo;
+  const pr_number = context.issue.number;
+
+  const labelsToRemove = managedLabels.filter(label => !finalLabels.includes(label));
+  for (const label of labelsToRemove) {
+    console.log(`Removing label: ${label}`);
+    try {
+      await github.rest.issues.removeLabel({
+        owner,
+        repo,
+        issue_number: pr_number,
+        name: label
+      });
+    } catch (error) {
+      console.log(`Failed to remove label ${label}:`, error.message);
+    }
+  }
+}
+
+module.exports = {
+  applyLabels,
+  removeOldLabels
+};