fix(auth): C3 review — surface seam not-found (no silent success), partial-reconcile-failure guidance, create validation order, concurrent-edit reconciler test

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Admin/ApiKeys.razor

@@ -146,7 +146,13 @@
         {
             var newEnabled = !key.Enabled;
             // The seam persists; there is no separate SaveChangesAsync.
-            await ApiKeyAdmin.SetEnabledAsync(key.KeyId, newEnabled);
+            var ok = await ApiKeyAdmin.SetEnabledAsync(key.KeyId, newEnabled);
+            if (!ok)
+            {
+                _toast.ShowError($"API key '{key.Name}' was not found — it may have been removed. Refreshing.");
+                await LoadDataAsync();
+                return;
+            }
             _toast.ShowSuccess($"API key '{key.Name}' {(newEnabled ? "enabled" : "disabled")}.");
             await LoadDataAsync();
         }
@@ -166,7 +172,13 @@
 
         try
         {
-            await ApiKeyAdmin.DeleteAsync(key.KeyId);
+            var ok = await ApiKeyAdmin.DeleteAsync(key.KeyId);
+            if (!ok)
+            {
+                _toast.ShowError($"API key '{key.Name}' was not found — it may have been removed. Refreshing.");
+                await LoadDataAsync();
+                return;
+            }
             _toast.ShowSuccess($"API key '{key.Name}' deleted.");
             await LoadDataAsync();
         }