feat: Partner hierarchy backoffice page (F41-F44 partial)

New nav entry, route, page. Renders the four-level tree
(Company/Project/Store/PaymentPoint) via AdminPartnerHierarchyFacade on top
of the core built in the previous commit - TEST/LIVE toggle, suspend/activate,
disable behind a confirmation (terminal + cascading, per contract §2), and a
read-only credentials list stating plainly that only the public key is ever
held.

Reload-after-action rather than local patch on suspend/activate/disable:
disable cascades to descendants server-side, so a local patch would leave
children showing a status they no longer have.

Company id is a constant for now (DEFAULT_COMPANY_ID) - company creation is
out of band per contract §4.3, and there is no company-selector UI yet.

Verified: 139/139 unit tests, arch:check clean, production build succeeds.

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

src/app/app.routes.ts

@@ -228,6 +228,15 @@ const coreRoutes: Routes = [
           breadcrumb: [{ labelKey: 'adminShell.nav.marketplaces' }]
         }
       },
+      {
+        path: 'partner-hierarchy',
+        loadComponent: () => import('./features/admin/partner-hierarchy/pages/admin-partner-hierarchy-page.component').then(m => m.AdminPartnerHierarchyPageComponent),
+        data: {
+          titleKey: 'adminShell.nav.partnerHierarchy',
+          descriptionKey: 'adminShell.nav.partnerHierarchy',
+          breadcrumb: [{ labelKey: 'adminShell.nav.partnerHierarchy' }]
+        }
+      },
       {
         path: 'audit',
         loadComponent: () => import('./features/admin/audit/pages/admin-audit-page.component').then(m => m.AdminAuditPageComponent),