perf(admin): implement server-side search and virtualization for tenant list

- Backend: Added 'search' parameter to TenantRepository and TenantService.
- Backend: Updated all Tenant list calls to support searching.
- Backend: Enhanced UserRepository.List to support cursor-based pagination and search.
- Frontend: Switched TenantListPage to use useInfiniteQuery for lazy loading.
- Frontend: Implemented list virtualization in TenantHierarchyView using @tanstack/react-virtual.
- Frontend: Added server-side search with debouncing (useDeferredValue).
- Fixed various Go compilation errors caused by method signature changes.

adminfront/src/lib/adminApi.ts

@@ -293,11 +293,12 @@ export async function fetchTenants(
   offset = 0,
   parentId?: string,
   cursor?: string,
+  search?: string,
 ) {
   const { data } = await apiClient.get<TenantListResponse>(
     "/v1/admin/tenants",
     {
-      params: { limit, offset, parentId, cursor },
+      params: { limit, offset, parentId, cursor, search },
     },
   );
   return data;