fix(wizard): don't animate silent ?aanvraag stamp — Firefox double-click on Next

The inschrijven/herregistratie wizards needed two clicks on "Volgende" to advance
in Firefox (and Zen). Root cause: picking a field (e.g. correspondentie) triggers
draft-sync's debounced create, which router.navigate()s to stamp ?aanvraag=<id>
into the URL. withViewTransitions() animated that same-route navigation, and for
the transition's duration Firefox's ::view-transition overlay swallows pointer
events (confirmed: elementFromPoint over the button returns the overlay, not the
button). Chrome sets pointer-events:none on the overlay so clicks pass through —
hence Firefox-only.

Fix: skip the view transition for same-route navigations (compare leaf routeConfig)
so the silent id-stamp doesn't animate; genuine page-to-page transitions still fade.

Verified in Firefox: page navs still animate (skipped:0), the ?aanvraag stamp is
skipped, and Post → single Next advances step 1 → 2. GREEN + a11y.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/app.config.ts

@@ -1,5 +1,6 @@
 import { ApplicationConfig, LOCALE_ID, isDevMode, provideBrowserGlobalErrorListeners } from '@angular/core';
 import { provideRouter, withViewTransitions } from '@angular/router';
+import type { ActivatedRouteSnapshot } from '@angular/router';
 import { provideHttpClient, withInterceptors } from '@angular/common/http';
 import { registerLocaleData } from '@angular/common';
 import localeNl from '@angular/common/locales/nl';
@@ -16,7 +17,26 @@ registerLocaleData(localeNl);
 export const appConfig: ApplicationConfig = {
   providers: [
     provideBrowserGlobalErrorListeners(),
-    provideRouter(routes, withViewTransitions()),
+    provideRouter(
+      routes,
+      // Cross-fade page-to-page navigations only. A silent same-route nav — e.g.
+      // draft-sync stamping `?aanvraag=<id>` into the URL mid-wizard — must NOT
+      // animate: for the transition's duration Firefox's `::view-transition`
+      // overlay swallows pointer events (Chrome sets pointer-events:none, so it
+      // doesn't), which loses a click landing on it and makes the wizard's "next"
+      // button need a second click. Skip the transition when the route is unchanged.
+      withViewTransitions({
+        onViewTransitionCreated: ({ transition, from, to }) => {
+          // `from`/`to` are the ROOT snapshots (the shared shell), so descend to the
+          // leaf before comparing — otherwise every navigation looks "same route".
+          const leaf = (r: ActivatedRouteSnapshot) => {
+            while (r.firstChild) r = r.firstChild;
+            return r;
+          };
+          if (leaf(from).routeConfig === leaf(to).routeConfig) transition.skipTransition();
+        },
+      }),
+    ),
     // Dev-only: the ?scenario= toggle must never reach a production build, where
     // a query param could otherwise force errors on the live app.
     provideHttpClient(withInterceptors(isDevMode() ? [scenarioInterceptor, roleInterceptor] : [])),