style: format frontend, docs and skills with prettier; add .prettierignore

One-time prettier --write so the new format:check CI gate starts green.
.prettierignore excludes generated (api-client.ts, documentation.json),
vendored (public/cibg-huisstijl), and backend (dotnet format owns it).

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

src/app/shared/ui/radio-group/radio-group.stories.ts

@@ -13,5 +13,11 @@ export default meta;
 type Story = StoryObj<RadioGroupComponent>;
 
 export const JaNee: Story = {
-  args: { name: 'voorbeeld', options: [{ value: 'ja', label: 'Ja' }, { value: 'nee', label: 'Nee' }] },
+  args: {
+    name: 'voorbeeld',
+    options: [
+      { value: 'ja', label: 'Ja' },
+      { value: 'nee', label: 'Nee' },
+    ],
+  },
 };