Add unit tests for PackRunAttestation and SealedInstallEnforcer

- Implement comprehensive tests for PackRunAttestationService, covering attestation generation, verification, and event emission.
- Add tests for SealedInstallEnforcer to validate sealed install requirements and enforcement logic.
- Introduce a MonacoLoaderService stub for testing purposes to prevent Monaco workers/styles from loading during Karma runs.

.gitea/workflows/release-manifest-verify.yml

@@ -0,0 +1,19 @@
+name: release-manifest-verify
+
+on:
+  push:
+    paths:
+      - deploy/releases/2025.09-stable.yaml
+      - deploy/releases/2025.09-airgap.yaml
+      - deploy/downloads/manifest.json
+      - ops/devops/release/check_release_manifest.py
+  workflow_dispatch:
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Validate release & downloads manifests
+        run: |
+          python ops/devops/release/check_release_manifest.py