test(api-client): generated BFF client is exposed and calls the endpoints (refs #66)

Scaffold libs/api-client (Nx Angular lib) and generate a typed HttpClient client
from services/bff/openapi.json with orval (node-based; Angular target integrates
with HttpClient interceptors for the S-08c auth token). A failing test drives the
public API: it expects an injectable BffApiV1Service to POST /self-service/registrations
and GET /openbaar/register (via HttpClientTesting), but the lib barrel doesn't export
the client yet, so it fails. Normalise the vitest target to 'test'. Green exposes it.

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

tsconfig.base.json

@@ -10,17 +10,13 @@
     "importHelpers": true,
     "target": "es2015",
     "module": "esnext",
-    "lib": [
-      "es2020",
-      "dom"
-    ],
+    "lib": ["es2020", "dom"],
     "skipLibCheck": true,
     "skipDefaultLibCheck": true,
     "baseUrl": ".",
-    "paths": {}
+    "paths": {
+      "api-client": ["./libs/api-client/src/index.ts"]
+    }
   },
-  "exclude": [
-    "node_modules",
-    "tmp"
-  ]
-}
+  "exclude": ["node_modules", "tmp"]
+}