test(portal-openbaar): drive the openbaar register page — list, search, empty state (refs #10)

Scaffolds the anonymous openbaar Angular app (mirrors self-service: standalone +
signals, NL DS via the ui lib, no auth) and adds a failing register-page spec:
loads the public register from the BFF on open, searches by term, and shows an
empty-state message. The stub page renders only the heading, so the list/search/
empty-state assertions fail (red).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/openbaar/tsconfig.spec.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": ["vitest/globals"]
+  },
+  "include": ["src/**/*.ts", "src/**/*.d.ts"]
+}