fix(auth): re-evaluate language-switcher link on navigation

The shell (and this switcher within it) is a persistent parent, so the
switcher's computed link only ever ran once at bootstrap against the
initial location.pathname. Navigating client-side afterward left it
frozen on that first route (typically /login), so switching language
from any other page sent you to the stale /en/login instead of the
current route — indistinguishable from being logged out, though the
session was untouched. Recompute on every completed Router navigation,
same toSignal(router.events...) idiom already used by the breadcrumb
in site-header.component.ts.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/shared/layout/language-switcher/language-switcher.component.ts

@@ -1,4 +1,7 @@
-import { Component, computed, input } from '@angular/core';
+import { Component, computed, inject, input } from '@angular/core';
+import { toSignal } from '@angular/core/rxjs-interop';
+import { NavigationEnd, Router } from '@angular/router';
+import { EMPTY, filter } from 'rxjs';
 import { Locale, localeLinks } from './locale-links';
 
 // CIBG-GAP EXTENSION: "Taal instellen" (designsystem.cibg.nl/componenten/taal-instellen) — no
@@ -14,6 +17,11 @@ import { Locale, localeLinks } from './locale-links';
  * is read from the baked `<base href>` (`/en/` → en, else nl) — the deployment truth, independent
  * of the app-config `LOCALE_ID`. Only functional where both locale bundles are served (the
  * localized build, e.g. `npm run serve:i18n`), not under plain `ng serve` (nl-only at `/`).
+ *
+ * The shell (and this switcher within it) is a persistent parent — only the routed child
+ * swaps — so `location.pathname` must be re-read on every completed navigation (same
+ * `toSignal(router.events...)` idiom as `site-header.component.ts`'s breadcrumb `url`), or the
+ * target link freezes at whichever route was active when the switcher was first constructed.
  */
 @Component({
   selector: 'app-language-switcher',
@@ -68,14 +76,21 @@ export class LanguageSwitcherComponent {
       ? location
       : ({ pathname: '/', search: '', hash: '' } as Location);
 
-  protected links = computed(() =>
-    localeLinks(
+  private router = inject(Router, { optional: true });
+  private nav = toSignal(
+    this.router?.events.pipe(filter((e) => e instanceof NavigationEnd)) ?? EMPTY,
+    { initialValue: null },
+  );
+
+  protected links = computed(() => {
+    this.nav(); // recompute on every completed navigation — loc.pathname is read fresh below
+    return localeLinks(
       this.loc.pathname,
       this.activeLocale() ?? this.detected,
       this.loc.search,
       this.loc.hash,
-    ),
-  );
+    );
+  });
 
   protected navLabel = $localize`:@@lang.navLabel:Taal / Language`;
   protected heading = $localize`:@@lang.heading:Kies een taal`;