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.

src/Web/StellaOps.Web/angular.json

@@ -91,6 +91,12 @@
             "tsConfig": "tsconfig.spec.json",
             "karmaConfig": "karma.conf.cjs",
             "inlineStyleLanguage": "scss",
+            "fileReplacements": [
+              {
+                "replace": "src/app/features/policy-studio/editor/monaco-loader.service.ts",
+                "with": "src/app/features/policy-studio/editor/monaco-loader.service.stub.ts"
+              }
+            ],
             "assets": [
               "src/favicon.ico",
               "src/assets",

src/Web/StellaOps.Web/src/app/features/policy-studio/editor/monaco-loader.service.stub.ts

@@ -0,0 +1,33 @@
+// Test-only stub to prevent Monaco workers/styles from loading during Karma runs.
+// Keeps the same public contract as the real MonacoLoaderService but returns a
+// lightweight in-memory implementation.
+export class MonacoLoaderService {
+  private readonly monaco = {
+    editor: {
+      createModel: (value: string) => {
+        let current = value;
+        return {
+          getValue: () => current,
+          setValue: (v: string) => (current = v),
+          dispose: () => undefined,
+        };
+      },
+      create: () => ({
+        onDidChangeModelContent: (_cb: () => void) => ({ dispose: () => undefined }),
+        dispose: () => undefined,
+      }),
+      setModelMarkers: (_model: unknown, _owner: string, _markers: any[]) => undefined,
+      setTheme: () => undefined,
+    },
+    languages: {
+      register: () => undefined,
+      setMonarchTokensProvider: () => undefined,
+      setLanguageConfiguration: () => undefined,
+    },
+    MarkerSeverity: { Error: 8, Warning: 4, Info: 2 },
+  };
+
+  load(): Promise<any> {
+    return Promise.resolve(this.monaco);
+  }
+}