refactor: rename Application → Aanvraag across the wire (Step 1/8)

The wire said Application, the domain said Aanvraag — one aggregate with
two names at every hop. Rename the backend DTOs and the /applications
route to /aanvragen, regenerate the typed client, and rename the frontend
adapter/store to match.

Renamed: ApplicationSummaryDto/DetailDto, CreateApplicationRequest,
SubmitApplicationRequest/Response → Aanvraag* equivalents;
ApplicationsAdapter/Store → AanvragenAdapter/Store;
applications.adapter.ts/applications.store.ts → aanvragen.*.

Left untouched: the admin Case/Zaak vocabulary (/admin/cases,
AdminCasesStore) — a separate read model, not part of this rename; the
internal BigRegister.Domain.Applications namespace and the Applications
EF table (renaming those needs a new EF migration, out of scope here).

Part of the dashboard-readability refactor (see the approved plan).

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

apps/ssp/src/app/registratie/application/admin-cases.store.spec.ts

@@ -1,7 +1,7 @@
 import { TestBed } from '@angular/core/testing';
 import { describe, it, expect, vi } from 'vitest';
 import { SUBMIT_FAILED } from '@shared/application/submit';
-import { ApplicationsAdapter } from '@registratie/infrastructure/applications.adapter';
+import { AanvragenAdapter } from '@registratie/infrastructure/aanvragen.adapter';
 import { AdminCasesStore } from './admin-cases.store';
 
 const summary = (id: string) => ({
@@ -14,9 +14,9 @@ const summary = (id: string) => ({
   owner: '19012345601',
 });
 
-function setup(adapter: Partial<ApplicationsAdapter>): AdminCasesStore {
+function setup(adapter: Partial<AanvragenAdapter>): AdminCasesStore {
   TestBed.configureTestingModule({
-    providers: [{ provide: ApplicationsAdapter, useValue: adapter }],
+    providers: [{ provide: AanvragenAdapter, useValue: adapter }],
   });
   return TestBed.inject(AdminCasesStore);
 }