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/link/link.component.ts

@@ -1,11 +1,11 @@
 import { Component, input } from '@angular/core';
 import { RouterLink } from '@angular/router';
 
-/** Atom: link. Internal router link styled as an RHC/Utrecht link. */
+/** Atom: link. Internal router link; CIBG/Bootstrap styles bare anchors. */
 @Component({
   selector: 'app-link',
   imports: [RouterLink],
-  template: `<a [routerLink]="to()" class="rhc-link nl-link utrecht-link"><ng-content /></a>`,
+  template: `<a [routerLink]="to()" class="link-primary"><ng-content /></a>`,
 })
 export class LinkComponent {
   to = input.required<string>();