feat: add CI E2E workflow with ntfy alerts

- Self-hosted runner on Tower
- Playwright E2E 23 tests
- ntfy notifications on pass/fail
- Runs on push to main + PRs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/ci-e2e.yml

@@ -0,0 +1,41 @@
+name: CI + E2E
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  e2e:
+    runs-on: self-hosted
+    timeout-minutes: 10
+    steps:
+      - name: Run E2E tests
+        id: e2e
+        run: |
+          cd /home/clems/mascarade/web
+          BASE_URL=http://localhost:3100 npx playwright test --reporter=line 2>&1 | tee /tmp/e2e-output.txt
+          PASSED=$(grep -oP '\d+ passed' /tmp/e2e-output.txt | grep -oP '\d+' || echo 0)
+          FAILED=$(grep -oP '\d+ failed' /tmp/e2e-output.txt | grep -oP '\d+' || echo 0)
+          echo "passed=$PASSED" >> $GITHUB_OUTPUT
+          echo "failed=$FAILED" >> $GITHUB_OUTPUT
+          if [ "${FAILED:-0}" != "0" ] && [ "${FAILED:-0}" != "" ]; then exit 1; fi
+
+      - name: Notify ntfy on failure
+        if: failure()
+        run: |
+          curl -s -d "E2E FAILED: ${{ steps.e2e.outputs.failed }} tests failed on $(date '+%H:%M')" \
+            -H "Title: Ops ER E2E Failed" \
+            -H "Priority: high" \
+            -H "Tags: rotating_light" \
+            https://ntfy.saillant.cc/ops-alerts 2>/dev/null || true
+
+      - name: Notify ntfy on success
+        if: success()
+        run: |
+          curl -s -d "E2E OK: ${{ steps.e2e.outputs.passed }} passed" \
+            -H "Title: Ops ER E2E Pass" \
+            -H "Priority: low" \
+            -H "Tags: white_check_mark" \
+            https://ntfy.saillant.cc/ops-alerts 2>/dev/null || true