fix(central-ui): resolve CentralUI-015..019 — pager windowing, logout CSRF, narrowed catch blocks, coverage; CentralUI-015 re-triaged Won't Fix

src/ScadaLink.CentralUI/Components/Shared/DialogService.cs

@@ -23,6 +23,13 @@ public class DialogService : IDialogService
     /// </summary>
     public DialogState? Current { get; private set; }
 
+    // CentralUI-015: the pending dialog result is held in a typed TCS that the
+    // host completes directly via Resolve(). The previous implementation
+    // projected the result through Task.ContinueWith(..., TaskScheduler.Default),
+    // which ran the projection lambda on a thread-pool thread. Completing a
+    // strongly-typed TCS directly removes that off-render-thread hop entirely —
+    // the awaiting caller resumes on whatever SynchronizationContext it captured
+    // (the Blazor renderer's, for an event-handler caller).
     private TaskCompletionSource<object?>? _tcs;
 
     public Task<bool> ConfirmAsync(string title, string message, bool danger = false)
@@ -32,7 +39,7 @@ public class DialogService : IDialogService
         _tcs = tcs;
         Current = new DialogState(title, DialogKind.Confirm, message, danger, PromptInitial: string.Empty, Placeholder: null);
         OnChange?.Invoke();
-        return tcs.Task.ContinueWith(t => t.Result is bool b && b, TaskScheduler.Default);
+        return Project(tcs.Task, static r => r is bool b && b);
     }
 
     public Task<string?> PromptAsync(string title, string label, string initialValue = "", string? placeholder = null)
@@ -42,7 +49,18 @@ public class DialogService : IDialogService
         _tcs = tcs;
         Current = new DialogState(title, DialogKind.Prompt, label, Danger: false, PromptInitial: initialValue, Placeholder: placeholder);
         OnChange?.Invoke();
-        return tcs.Task.ContinueWith(t => t.Result as string, TaskScheduler.Default);
+        return Project(tcs.Task, static r => r as string);
+    }
+
+    /// <summary>
+    /// Awaits the host's result and projects it to the caller's type. The
+    /// <c>await</c> here resumes on the caller's captured context (the renderer
+    /// sync context for an event-handler caller), not a thread-pool thread.
+    /// </summary>
+    private static async Task<TResult> Project<TResult>(Task<object?> source, Func<object?, TResult> selector)
+    {
+        var result = await source.ConfigureAwait(false);
+        return selector(result);
     }
 
     /// <summary>