fix(admin): add InteractiveServer render mode to remaining interactive pages

ModbusAddressPreview (@bind on dropdowns + child ModbusAddressEditor with @oninput),
ModbusDiagnostics (@onclick Refresh), and NewCluster (EditForm with Nav.NavigateTo on submit)
were missed in the first pass — all three require interactivity but had no @rendermode.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/NewCluster.razor

@@ -1,8 +1,10 @@
 @page "/clusters/new"
 @using System.ComponentModel.DataAnnotations
+@using Microsoft.AspNetCore.Components.Web
 @using ZB.MOM.WW.OtOpcUa.Admin.Services
 @using ZB.MOM.WW.OtOpcUa.Configuration.Entities
 @using ZB.MOM.WW.OtOpcUa.Configuration.Enums
+@rendermode RenderMode.InteractiveServer
 @inject ClusterService ClusterSvc
 @inject GenerationService GenerationSvc
 @inject NavigationManager Nav

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Modbus/ModbusAddressPreview.razor

@@ -1,5 +1,7 @@
 @page "/modbus/address-preview"
+@using Microsoft.AspNetCore.Components.Web
 @using ZB.MOM.WW.OtOpcUa.Driver.Modbus
+@rendermode RenderMode.InteractiveServer
 
 @*
     #149 — standalone preview / sanity-check tool for Modbus address strings. The Admin UI

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Modbus/ModbusDiagnostics.razor

@@ -1,5 +1,7 @@
 @page "/modbus/diagnostics/{DriverInstanceId}"
+@using Microsoft.AspNetCore.Components.Web
 @using ZB.MOM.WW.OtOpcUa.Admin.Services
+@rendermode RenderMode.InteractiveServer
 @inject DriverDiagnosticsClient Diagnostics
 
 @*