feat(design): re-theme to CIBG Huisstijl (Bootstrap 5.2), replacing RHC/Utrecht

The portal now adheres to the CIBG design system (designsystem.cibg.nl) — a customized
Bootstrap 5.2 build — replacing the Rijkshuisstijl-Community / Utrecht theme. See ADR-0003.

- Vendor @cibg/huisstijl@3.22.0 under public/cibg-huisstijl/, loaded via a <link> in
  index.html (Storybook serves it via staticDirs). Drop the two @rijkshuisstijl-community deps.
- Token bridge in styles.scss: redefine the app's ~54 --rhc-* tokens onto CIBG/--bs-* values,
  so components keep referencing tokens (no 300+ site rewrite). System-font stack; licensed
  RO/Rijks text fonts intentionally not shipped.
- Re-skin every shared atom to Bootstrap/CIBG classes (btn, form-control, form-check-*,
  table, breadcrumb, …) keeping their input() APIs. alert is hand-rolled (CIBG drops .alert);
  local .card/.badge renamed to avoid Bootstrap collisions.
- Domain pages: drop stray rhc-*/utrecht-* classes; registration-table → table table-striped.

Verified: build green, check:tokens OK, lint clean, 174 tests pass, build-storybook OK,
and the served build loads the vendored CSS (200, .btn-primary present).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -18,25 +18,27 @@ export const JA_NEE: RadioOption[] = [
 @Component({
   selector: 'app-radio-group',
   styles: [`
-    .rhc-radio-option {
+    .radio-option {
       display: flex;
       align-items: center;
       gap: var(--rhc-space-max-md);
       padding-block: var(--rhc-space-max-sm);
+      margin: 0;
     }
+    /* form-check-input floats/margins for the .form-check layout; here it's flex-aligned. */
+    .radio-option .form-check-input { margin: 0; float: none; }
   `],
   template: `
     <div
-      class="utrecht-form-field-radio-group"
       role="radiogroup"
       [attr.aria-labelledby]="name() + '-label'"
       [attr.aria-invalid]="invalid() ? 'true' : null"
       [attr.aria-describedby]="invalid() ? name() + '-error' : null">
       @for (opt of options(); track opt.value) {
-        <label class="utrecht-form-label utrecht-form-label--radio-button rhc-radio-option">
+        <label class="form-check-label radio-option">
           <input
-            class="utrecht-radio-button"
-            [class.utrecht-radio-button--checked]="value === opt.value"
+            class="form-check-input"
+            [class.is-invalid]="invalid()"
             type="radio"
             [name]="name()"
             [value]="opt.value"