v3(b1-wp4b): make AdminUI compile against greenfield schema behind Batch-2/3 stubs

Namespace entity + NamespaceKind retired; DriverInstance dropped NamespaceId;
Tag is raw-only (no EquipmentId/DriverInstanceId/FullName/FolderPath); driver
options replaced pre-declared Tags with RawTags. Stub the retired surfaces so
the AdminUI + Host build green; real Raw/UNS authoring arrives in v3 Batch 2/3.

- ClusterNamespaces/NamespaceEdit: bodies replaced with 'Namespaces retired' banner
- DriverIdentitySection: dropped Namespace dropdown + NamespaceId model field
- 8 driver pages: dropped Namespace binding; retired the pre-declared Tags editor
  (replaced with a '/raw Batch 2' note); multi-device pages keep their Devices editor
- UnsTreeService: equipment-tag counts/list -> empty; Create/UpdateTag -> failure
  result ('Tag authoring moved to the Raw tree (/raw) in v3 Batch 2'); Namespace/
  driver-binding queries removed
- IScriptTagCatalog: project surviving Tag columns only (path from TagConfig FullName, else Name)
- OpcUaClientTagConfigEditor: rebind stale FullName -> model's NodeId
- ClusterDrivers: drop retired NamespaceId column

AdminUI + Host build 0/0. AdminUI.Tests / Host.IntegrationTests remain red (WP6).

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/ClusterNamespaces.razor

@@ -1,81 +1,23 @@
 @page "/clusters/{ClusterId}/namespaces"
 @attribute [Authorize(Policy = AdminUiPolicies.AuthenticatedRead)]
 @rendermode RenderMode.InteractiveServer
-@using Microsoft.EntityFrameworkCore
-@using ZB.MOM.WW.OtOpcUa.Configuration
-@using ZB.MOM.WW.OtOpcUa.Configuration.Entities
-@inject IDbContextFactory<OtOpcUaConfigDbContext> DbFactory
 
 <div class="d-flex justify-content-between align-items-center mb-3">
     <h4 class="mb-0">Namespaces &middot; <span class="mono">@ClusterId</span></h4>
-    <a href="/clusters/@ClusterId/namespaces/new" class="btn btn-primary btn-sm">New namespace</a>
 </div>
 
 <ClusterNav ClusterId="@ClusterId" ActiveTab="namespaces" />
 
-@if (_rows is null)
-{
-    <p>Loading…</p>
-}
-else
-{
-    <section class="panel notice rise" style="animation-delay:.02s">
-        Namespaces are content (decision #123) — they're served at the OPC UA endpoint and bound
-        to driver instances. NamespaceUri must be unique fleet-wide.
-    </section>
-
-    <section class="panel rise mt-3" style="animation-delay:.08s">
-        <div class="panel-head">@_rows.Count namespace@(_rows.Count == 1 ? "" : "s")</div>
-        @if (_rows.Count == 0)
-        {
-            <div style="padding:1rem" class="text-muted">No namespaces defined for this cluster.</div>
-        }
-        else
-        {
-            <div class="table-wrap">
-                <table class="data-table">
-                    <thead>
-                        <tr>
-                            <th>NamespaceId</th>
-                            <th>Kind</th>
-                            <th>URI</th>
-                            <th>Status</th>
-                            <th>Notes</th>
-                            <th></th>
-                        </tr>
-                    </thead>
-                    <tbody>
-                        @foreach (var n in _rows)
-                        {
-                            <tr>
-                                <td><span class="mono">@n.NamespaceId</span></td>
-                                <td>@n.Kind</td>
-                                <td><span class="mono small">@n.NamespaceUri</span></td>
-                                <td>
-                                    @if (n.Enabled) { <span class="chip chip-ok">Enabled</span> }
-                                    else { <span class="chip chip-idle">Disabled</span> }
-                                </td>
-                                <td class="text-muted small">@(n.Notes ?? "")</td>
-                                <td><a href="/clusters/@ClusterId/namespaces/@n.NamespaceId" class="btn btn-sm btn-outline-primary">Edit</a></td>
-                            </tr>
-                        }
-                    </tbody>
-                </table>
-            </div>
-        }
-    </section>
-}
+<section class="panel notice rise" style="animation-delay:.02s">
+    <div class="panel-head">Namespaces are retired in v3</div>
+    <div style="padding:1rem">
+        The <code>Namespace</code> entity has been removed. The v3 Raw/UNS split replaces it —
+        raw driver folders and the unified namespace are managed on the <strong>/raw</strong> and
+        <strong>/uns</strong> pages, arriving in v3 Batch 2/3. This page is a placeholder so existing
+        links do not 404.
+    </div>
+</section>
 
 @code {
     [Parameter] public string ClusterId { get; set; } = "";
-    private List<Namespace>? _rows;
-
-    protected override async Task OnInitializedAsync()
-    {
-        await using var db = await DbFactory.CreateDbContextAsync();
-        _rows = await db.Namespaces.AsNoTracking()
-            .Where(n => n.ClusterId == ClusterId)
-            .OrderBy(n => n.NamespaceId)
-            .ToListAsync();
-    }
 }