ci: Tune instance-ai discovery eval runner and triggers (#31697)

Co-authored-by: n8n-cat-bot[bot] <n8n-cat-bot[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/ci-pull-requests.yml

@@ -340,6 +340,7 @@ jobs:
       needs.install-and-build.result == 'success' &&
       needs.install-and-build.outputs.instance_ai_workflow_eval == 'true' &&
       github.repository == 'n8n-io/n8n' &&
+      github.event_name != 'merge_group' &&
       (github.event_name != 'pull_request' || !github.event.pull_request.head.repo.fork)
     uses: ./.github/workflows/test-evals-discovery.yml
     with:

.github/workflows/test-evals-discovery.yml

@@ -36,7 +36,7 @@ on:
 jobs:
   run-discovery-evals:
     name: 'Run Discovery Evals'
-    runs-on: blacksmith-2vcpu-ubuntu-2204
+    runs-on: blacksmith-4vcpu-ubuntu-2204
     timeout-minutes: 15
     permissions:
       contents: read
@@ -51,8 +51,6 @@ jobs:
 
       - name: Setup Environment
         uses: ./.github/actions/setup-nodejs
-        with:
-          build-command: 'pnpm build'
 
       - name: Export Node Types
         run: |