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/layout/breadcrumb/breadcrumb.component.ts

@@ -26,10 +26,10 @@ export interface BreadcrumbItem {
     :host(.inverse) .sep { color: var(--rhc-color-foreground-on-primary); }
   `],
   template: `
-    <nav class="rhc-breadcrumb-nav utrecht-breadcrumb-nav" i18n-aria-label="@@breadcrumb.aria" aria-label="Kruimelpad">
-      <ol class="utrecht-breadcrumb-nav__list list">
+    <nav i18n-aria-label="@@breadcrumb.aria" aria-label="Kruimelpad">
+      <ol class="list">
         @for (item of items(); track item.label; let last = $last; let first = $first) {
-          <li class="utrecht-breadcrumb-nav__item crumb">
+          <li class="crumb">
             @if (!first) { <span class="sep" aria-hidden="true">›</span> }
             @if (item.link && !last) {
               <a [routerLink]="item.link">{{ item.label }}</a>

src/app/shared/layout/page-shell/page-shell.component.ts

@@ -22,7 +22,7 @@ import { LinkComponent } from '@shared/ui/link/link.component';
       }
       <app-heading [level]="1">{{ heading() }}</app-heading>
       @if (intro()) {
-        <p class="rhc-paragraph intro">{{ intro() }}</p>
+        <p class="intro">{{ intro() }}</p>
       }
       <ng-content />
     </div>

src/app/shared/layout/shell/shell.component.ts

@@ -11,16 +11,17 @@ import { DebugStateComponent } from '@shared/ui/debug-state/debug-state.componen
   imports: [RouterOutlet, SiteHeaderComponent, SiteFooterComponent, DebugStateComponent],
   styles: [`
     :host{display:block}
-    .skip{position:absolute;left:var(--app-skip-link-offset)}
-    .layout{min-block-size:100vh;align-items:stretch}
+    .skip{position:absolute;left:var(--app-skip-link-offset);z-index:1030}
+    .skip:focus{left:var(--rhc-space-max-md);top:var(--rhc-space-max-md);background:var(--rhc-color-wit);padding:var(--rhc-space-max-sm) var(--rhc-space-max-md);border-radius:var(--rhc-border-radius-sm)}
+    .layout{display:flex;flex-direction:column;min-block-size:100vh}
     .main{flex:1;inline-size:100%;box-sizing:border-box}
     .content{max-inline-size:var(--app-content-max);margin-inline:auto;padding:var(--rhc-space-max-3xl) var(--rhc-space-max-2xl);box-sizing:border-box}
   `],
   template: `
-    <a href="#main" class="rhc-skip-link skip" i18n="@@shell.skipLink">Naar de inhoud</a>
-    <div class="utrecht-page-layout utrecht-page-layout--stretch layout">
+    <a href="#main" class="skip" i18n="@@shell.skipLink">Naar de inhoud</a>
+    <div class="layout">
       <app-site-header />
-      <main id="main" class="utrecht-page-content main">
+      <main id="main" class="main">
         <div class="content">
           <router-outlet />
         </div>

src/app/shared/layout/site-footer/site-footer.component.ts

@@ -19,7 +19,7 @@ import { Component } from '@angular/core';
     .meta{inline-size:100%;border-block-start:var(--rhc-border-width-sm) solid var(--rhc-color-lintblauw-600);margin-block-start:var(--rhc-space-max-xl);padding-block-start:var(--rhc-space-max-lg);font-size:var(--rhc-text-font-size-sm);opacity:.85}
   `],
   template: `
-    <footer class="utrecht-page-footer bar">
+    <footer class="bar">
       <div class="inner">
         <div>
           <div class="tagline" i18n="@@footer.tagline">De Rijksoverheid. Voor Nederland.</div>

src/app/shared/layout/wizard-shell/wizard-shell.component.ts

@@ -35,11 +35,11 @@ export type WizardStatus = 'editing' | 'submitting' | 'submitted' | 'failed';
     @switch (status()) {
       @case ('editing') {
         <app-stepper class="app-section" [steps]="steps()" [current]="current()" />
-        <h2 #stepHeading tabindex="-1" class="rhc-heading nl-heading--level-2 app-section">{{ stepTitle() }}</h2>
+        <h2 #stepHeading tabindex="-1" class="app-section">{{ stepTitle() }}</h2>
         @if (errors().length) {
           <div #errorSummary tabindex="-1" role="alert" aria-labelledby="wizard-error-title" class="app-section">
             <app-alert type="error">
-              <h3 id="wizard-error-title" class="rhc-heading nl-heading--level-3 es-title" i18n="@@wizard.errorTitle">Er ging iets mis met uw invoer</h3>
+              <h3 id="wizard-error-title" class="es-title" i18n="@@wizard.errorTitle">Er ging iets mis met uw invoer</h3>
               <ul class="es-list">
                 @for (e of errors(); track e.id) {
                   <li><a [href]="'#' + e.id" (click)="goToField($event, e.id)">{{ e.message }}</a></li>