feat(registratie): WP-36 — admin cases page + admin delete

Admin-only overview of all cases across owners + an admin delete, gated by a new
`cases:manage` capability (Authz role→cap + CanManageCases + CasesAdmin gate;
FE capability + guard + nav + role.interceptor prefix — the org-template/stamdata
recipe). Backend adds ApplicationStore.ListAll()/DeleteAny() and GET /admin/cases +
DELETE /admin/cases/{id}; admin delete removes ANY case incl. submitted. Page lives
in registratie/ui (owns the Aanvraag aggregate; reuses aanvraag-view + parse),
routed /beheer/zaken; delete guarded by a native confirm, optimistic with rollback.
Typed client regenerated (documents the new endpoints + owner field).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/tests/BigRegister.Tests/OrgTemplateEndpointTests.cs

@@ -201,7 +201,7 @@ public class OrgTemplateEndpointTests(TestWebApplicationFactory factory) : IClas
   {
     var res = await _client.SendAsync(Req(HttpMethod.Get, "/api/v1/me", role: "admin"));
     var me = await res.Content.ReadFromJsonAsync<MeDto>();
-    Assert.Equal(new[] { "orgtemplate:edit", "stamdata:edit" }, me!.Capabilities);
+    Assert.Equal(new[] { "orgtemplate:edit", "stamdata:edit", "cases:manage" }, me!.Capabilities);
   }
 
   [Fact]