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/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>