feat(ui/deployment): consolidate sites/areas/instances into Topology page

Single /deployment/topology page replaces /deployment/instances (legacy URL
preserved as a secondary @page directive) and the /admin/areas* CRUD pages.
TreeView with Site → Area → Instance, V1–V7 visual guide (bi-building /
bi-diagram-3 / bi-box), always-visible empty containers, search dim, F2
inline area rename, and right-click context menus per node kind (Add Area,
Move to Area…, lifecycle actions, etc.).

Adds AreaService.MoveAreaAsync with cycle prevention, same-site enforcement,
and name-collision check at the new parent. Instance rename intentionally
out of scope — UniqueName is the site-side actor identity, requires its own
design pass.

src/ScadaLink.CentralUI/Components/Pages/Deployment/InstanceCreate.razor

@@ -14,7 +14,7 @@
 
 <div class="container-fluid mt-3">
     <div class="d-flex align-items-center mb-3">
-        <a href="/deployment/instances" class="btn btn-outline-secondary btn-sm me-3">&larr; Back</a>
+        <a href="/deployment/topology" class="btn btn-outline-secondary btn-sm me-3">&larr; Back</a>
         <h4 class="mb-0">Create Instance</h4>
     </div>
 
@@ -74,6 +74,9 @@
 </div>
 
 @code {
+    [SupplyParameterFromQuery] public int? SiteId { get; set; }
+    [SupplyParameterFromQuery] public int? AreaId { get; set; }
+
     private List<Site> _sites = new();
     private List<Template> _templates = new();
     private List<Area> _allAreas = new();
@@ -98,6 +101,15 @@
                 var areas = await TemplateEngineRepository.GetAreasBySiteIdAsync(site.Id);
                 _allAreas.AddRange(areas);
             }
+
+            if (SiteId is int sid && _sites.Any(s => s.Id == sid))
+            {
+                _createSiteId = sid;
+            }
+            if (AreaId is int aid && _allAreas.Any(a => a.Id == aid && a.SiteId == _createSiteId))
+            {
+                _createAreaId = aid;
+            }
         }
         catch (Exception ex)
         {
@@ -120,7 +132,7 @@
                 _createName.Trim(), _createTemplateId, _createSiteId, _createAreaId == 0 ? null : _createAreaId, user);
             if (result.IsSuccess)
             {
-                NavigationManager.NavigateTo("/deployment/instances");
+                NavigationManager.NavigateTo("/deployment/topology");
             }
             else
             {
@@ -133,7 +145,7 @@
         }
     }
 
-    private void GoBack() => NavigationManager.NavigateTo("/deployment/instances");
+    private void GoBack() => NavigationManager.NavigateTo("/deployment/topology");
 
     private async Task<string> GetCurrentUserAsync()
     {