ci: Add nightly E2E run with VM expression engine (#27964)

.github/WORKFLOWS.md

@@ -72,6 +72,7 @@ Complete reference for n8n's `.github/` folder.
 │  │  (cron)  │    │  ├─ docker-build-push (nightly)  │───▶│   Images   │   │
 │  └──────────┘    │  ├─ test-benchmark-nightly       │───▶│  Metrics   │   │
 │                  │  ├─ test-workflows-nightly       │    └────────────┘   │
+│                  │  ├─ test-e2e-vm-expressions      │                     │
 │                  │  └─ test-e2e-coverage-weekly     │                     │
 │                  └──────────────────────────────────┘                     │
 │                                                                            │
@@ -258,6 +259,10 @@ release-publish.yml
 test-workflows-nightly.yml
     └──────────────────────────▶  test-workflows-callable.yml
 
+test-e2e-vm-expressions-nightly.yml
+    └──────────────────────────▶  test-e2e-ci-reusable.yml
+                                      └──────────▶  test-e2e-reusable.yml
+
 PR Comment Dispatchers (triggered by /command in PR comments):
 test-workflows-pr-comment.yml
     └──────────────────────────▶  test-workflows-callable.yml
@@ -370,6 +375,7 @@ Push to master/1.x
 | Daily 00:00               | `util-check-docs-urls.yml`        | Doc link validation      |
 | Daily 01:30, 02:30, 03:30 | `test-benchmark-nightly.yml`      | Performance benchmarks   |
 | Daily 02:00               | `test-workflows-nightly.yml`      | Workflow tests           |
+| Daily 04:00               | `test-e2e-vm-expressions-nightly.yml`| VM expression E2E     |
 | Daily 05:00               | `test-benchmark-destroy-nightly.yml`| Cleanup benchmark env  |
 | Monday 00:00              | `util-update-node-popularity.yml` | Node usage stats         |
 | Monday 02:00              | `test-e2e-coverage-weekly.yml`    | Weekly E2E coverage      |

.github/workflows/test-e2e-vm-expressions-nightly.yml

@@ -0,0 +1,33 @@
+name: 'Test: E2E VM Expressions Nightly'
+
+on:
+  schedule:
+    - cron: '0 4 * * *'
+  workflow_dispatch:
+    inputs:
+      branch:
+        description: 'GitHub branch/ref to test'
+        required: false
+        type: string
+        default: 'master'
+
+jobs:
+  e2e-vm-expressions:
+    uses: ./.github/workflows/test-e2e-ci-reusable.yml
+    with:
+      branch: ${{ github.event_name == 'schedule' && 'master' || inputs.branch }}
+      n8n-env: '{"N8N_EXPRESSION_ENGINE":"vm"}'
+    secrets: inherit
+
+  notify-on-failure:
+    name: Notify Slack on failure
+    runs-on: ubuntu-slim
+    needs: [e2e-vm-expressions]
+    if: failure() && github.event_name == 'schedule'
+    steps:
+      - uses: act10ns/slack@44541246747a30eb3102d87f7a4cc5471b0ffb7d # v2.1.0
+        with:
+          status: ${{ job.status }}
+          channel: '#project-secure-expression-evaluation'
+          webhook-url: ${{ secrets.SLACK_WEBHOOK_URL }}
+          message: "VM expression E2E nightly failed - ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"