ci: comment PR artifacts from validation run

.github/workflows/pr-build.yml

@@ -10,6 +10,8 @@ on:
 permissions:
   contents: read
   actions: write
+  issues: write
+  pull-requests: write
 
 concurrency:
   group: pr-build-${{ github.event.pull_request.number }}
@@ -54,3 +56,76 @@ jobs:
       actions_artifacts_retention_days: 7
       actions_artifacts_name_prefix: pr-${{ github.event.pull_request.number }}-${{ github.event.pull_request.head.sha }}-
       set_versions: false
+
+  comment-artifacts:
+    needs:
+      - authorize
+      - build
+    if: ${{ always() && needs.authorize.outputs.allowed == 'true' }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Get PR number
+        id: get-pr
+        uses: bcgov/action-get-pr@v0.1.1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Comment with artifact download link
+        uses: actions/github-script@v8
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+            const prNumber = Number('${{ steps.get-pr.outputs.pr }}');
+            if (!prNumber) {
+              core.setFailed('Failed to resolve PR number.');
+              return;
+            }
+
+            const artifacts = await github.paginate(
+              github.rest.actions.listWorkflowRunArtifacts,
+              { owner, repo, run_id: context.runId, per_page: 100 }
+            );
+            const active = artifacts.filter((a) => !a.expired);
+
+            const marker = '<!-- codenomad-pr-artifacts -->';
+            const runUrl = `https://github.com/${owner}/${repo}/actions/runs/${context.runId}`;
+            const retentionDays = 7;
+            const artifactsBlock = active.length
+              ? ['Artifacts:', ...active.map((a) => `- ${a.name}`)].join('\n')
+              : 'Artifacts: (none found on this run)';
+
+            const body = [
+              marker,
+              'PR builds are available as GitHub Actions artifacts:',
+              '',
+              runUrl,
+              '',
+              `Artifacts expire in ${retentionDays} days.`,
+              artifactsBlock,
+            ].join('\n');
+
+            const comments = await github.paginate(
+              github.rest.issues.listComments,
+              { owner, repo, issue_number: prNumber, per_page: 100 }
+            );
+            const existing = comments.find((c) => (c.body || '').includes(marker));
+
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner,
+                repo,
+                comment_id: existing.id,
+                body,
+              });
+              core.info(`Updated existing artifacts comment: ${existing.html_url}`);
+            } else {
+              const created = await github.rest.issues.createComment({
+                owner,
+                repo,
+                issue_number: prNumber,
+                body,
+              });
+              core.info(`Created artifacts comment: ${created.data.html_url}`);
+            }