fix(central-ui): resolve CentralUI-020..025 — auth-ping idle logout, DebugView race, push-handler disposal guard, JS-interop catch narrowing, claim-constant helper, SessionExpiry tests

src/ScadaLink.CentralUI/Components/Pages/Monitoring/ParkedMessages.razor

@@ -10,6 +10,7 @@
 @inject CommunicationService CommunicationService
 @inject IJSRuntime JS
 @inject IDialogService Dialog
+@inject ILogger<ParkedMessages> Logger
 
 <div class="container-fluid mt-3">
     <ToastNotification @ref="_toast" />
@@ -694,7 +695,18 @@
             await JS.InvokeVoidAsync("navigator.clipboard.writeText", text);
             _toast.ShowSuccess("Copied to clipboard.");
         }
-        catch { _toast.ShowError("Copy failed."); }
+        catch (JSDisconnectedException)
+        {
+            // Circuit gone — the page is being torn down; nothing to surface.
+            // CentralUI-023: distinguished from a genuine interop failure.
+        }
+        catch (JSException ex)
+        {
+            // A real clipboard failure (e.g. permission denied) — surface it to
+            // the user and log it so it is not invisible in production.
+            Logger.LogWarning(ex, "Clipboard copy failed.");
+            _toast.ShowError("Copy failed.");
+        }
     }
 
     // ── Helpers ──