feat: structured telemetry, post-dismiss verify, stale-data indicator, archival warning (#718)

Dashboard/Controls/AlertsHistoryContent.xaml

@@ -92,6 +92,8 @@
                     Margin="4,0,0,0" Padding="10,4" MinWidth="70"/>
             <TextBlock x:Name="AlertCountIndicator" Text="" Margin="12,0,0,0" VerticalAlignment="Center"
                        FontStyle="Italic" Foreground="{DynamicResource AccentBrush}" FontWeight="SemiBold"/>
+            <TextBlock x:Name="LastRefreshedIndicator" Text="" Margin="12,0,0,0" VerticalAlignment="Center"
+                       FontSize="11" Foreground="{DynamicResource ForegroundMutedBrush}"/>
         </StackPanel>
 
         <!-- DataGrid -->

Dashboard/Controls/AlertsHistoryContent.xaml.cs

@@ -14,6 +14,7 @@
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Controls.Primitives;
+using System.Windows.Threading;
 using Microsoft.Win32;
 using PerformanceMonitorDashboard.Helpers;
 using PerformanceMonitorDashboard.Models;
@@ -28,6 +29,8 @@ public partial class AlertsHistoryContent : UserControl
         public MuteRuleService? MuteRuleService { get; set; }
 
         private List<AlertHistoryDisplayItem> _allAlerts = new();
+        private DateTime? _lastRefreshed;
+        private readonly DispatcherTimer _staleDataTimer;
 
         /* Column filter state */
         private readonly Dictionary<string, ColumnFilterState> _columnFilters = new();
@@ -37,6 +40,9 @@ public partial class AlertsHistoryContent : UserControl
         public AlertsHistoryContent()
         {
             InitializeComponent();
+            _staleDataTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(10) };
+            _staleDataTimer.Tick += StaleDataTimer_Tick;
+            _staleDataTimer.Start();
         }
 
         /// <summary>
@@ -78,6 +84,7 @@ private void LoadAlerts()
                 DetailText = e.DetailText
             }).ToList();
 
+            _lastRefreshed = DateTime.UtcNow;
             ApplyFilters();
         }
 
@@ -112,6 +119,7 @@ private void ApplyFilters()
             AlertsDataGrid.ItemsSource = list;
             NoAlertsMessage.Visibility = list.Count == 0 ? Visibility.Visible : Visibility.Collapsed;
             AlertCountIndicator.Text = list.Count > 0 ? $"{list.Count} alert(s)" : "";
+            UpdateStaleDataIndicator();
 
             /* Populate server filter if needed */
             PopulateServerFilter();
@@ -184,6 +192,28 @@ private static string GetStatusDisplay(AlertLogEntry entry)
             return entry.AlertSent ? "Delivered" : "Shown";
         }
 
+        #region Stale Data Indicator
+
+        private void StaleDataTimer_Tick(object? sender, EventArgs e)
+        {
+            UpdateStaleDataIndicator();
+        }
+
+        private void UpdateStaleDataIndicator()
+        {
+            if (_lastRefreshed.HasValue)
+            {
+                var elapsed = DateTime.UtcNow - _lastRefreshed.Value;
+                LastRefreshedIndicator.Text = elapsed.TotalSeconds < 5
+                    ? "Refreshed just now"
+                    : elapsed.TotalMinutes < 1
+                        ? $"Refreshed {(int)elapsed.TotalSeconds}s ago"
+                        : $"Refreshed {(int)elapsed.TotalMinutes}m ago";
+            }
+        }
+
+        #endregion
+
         #region Event Handlers
 
         private void TimeRangeComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
@@ -223,7 +253,9 @@ private void DismissSelected_Click(object sender, RoutedEventArgs e)
                 .Select(s => (s.AlertTime, s.ServerName, s.MetricName))
                 .ToList();
 
+            Logger.Info($"[AlertDismiss] Action=DismissSelected, Requested={selected.Count}");
             service.HideAlerts(keys);
+            Logger.Info($"[AlertDismiss] Action=DismissSelected, Result=Complete, Hidden={selected.Count}");
             LoadAlerts();
             AlertsDismissed?.Invoke(this, EventArgs.Empty);
         }
@@ -252,7 +284,9 @@ private void DismissAll_Click(object sender, RoutedEventArgs e)
                 serverName = serverItem.Content?.ToString();
             }
 
+            Logger.Info($"[AlertDismiss] Action=DismissAll, HoursBack={hoursBack}, Server={serverName ?? "all"}");
             service.HideAllAlerts(hoursBack > 0 ? hoursBack : 8760, serverName);
+            Logger.Info($"[AlertDismiss] Action=DismissAll, Result=Complete");
             LoadAlerts();
             AlertsDismissed?.Invoke(this, EventArgs.Empty);
         }

Lite/Controls/AlertsHistoryTab.xaml

@@ -94,6 +94,10 @@
                     Margin="4,0,0,0" Padding="10,4" MinWidth="70"/>
             <TextBlock x:Name="AlertCountIndicator" Text="" Margin="12,0,0,0" VerticalAlignment="Center"
                        FontStyle="Italic" Foreground="{DynamicResource AccentBrush}" FontWeight="SemiBold"/>
+            <TextBlock x:Name="LastRefreshedIndicator" Text="" Margin="12,0,0,0" VerticalAlignment="Center"
+                       FontSize="11" Foreground="{DynamicResource ForegroundMutedBrush}"/>
+            <TextBlock x:Name="ArchivalWarning" Text="" Margin="8,0,0,0" VerticalAlignment="Center"
+                       FontSize="11" Foreground="#FFCC6600" FontWeight="SemiBold" Visibility="Collapsed"/>
         </StackPanel>
 
         <!-- DataGrid -->

Lite/Controls/AlertsHistoryTab.xaml.cs

@@ -15,6 +15,7 @@
 using System.Windows.Controls;
 using System.Windows.Controls.Primitives;
 using System.Windows.Data;
+using System.Windows.Threading;
 using Microsoft.Win32;
 using PerformanceMonitorLite.Controls;
 using PerformanceMonitorLite.Models;
@@ -28,12 +29,16 @@ public partial class AlertsHistoryTab : UserControl
     private DataGridFilterManager<AlertHistoryRow>? _filterManager;
     private Popup? _filterPopup;
     private ColumnFilterPopup? _filterPopupContent;
+    private DateTime? _lastRefreshed;
+    private readonly DispatcherTimer _staleDataTimer;
 
     public MuteRuleService? MuteRuleService { get; set; }
 
     public AlertsHistoryTab()
     {
         InitializeComponent();
+        _staleDataTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(10) };
+        _staleDataTimer.Tick += StaleDataTimer_Tick;
     }
 
     /// <summary>
@@ -43,6 +48,7 @@ public void Initialize(LocalDataService dataService)
     {
         _dataService = dataService;
         _filterManager = new DataGridFilterManager<AlertHistoryRow>(AlertsDataGrid);
+        _staleDataTimer.Start();
     }
 
     /// <summary>
@@ -74,6 +80,9 @@ private async System.Threading.Tasks.Task LoadAlertsAsync()
             AlertCountIndicator.Text = displayCount > 0 ? $"{displayCount} alert(s)" : "";
             AppLogger.Debug("AlertsHistory", $"Loaded {displayCount} alert(s) (query returned {alerts.Count}, hoursBack={hoursBack}, serverId={serverId?.ToString() ?? "all"})");
 
+            _lastRefreshed = DateTime.UtcNow;
+            UpdateStaleDataIndicator();
+
             PopulateServerFilter(alerts);
         }
         catch (Exception ex)
@@ -197,6 +206,39 @@ private void FilterPopup_FilterCleared(object? sender, EventArgs e)
 
     #endregion
 
+    #region Stale Data Indicator
+
+    private void StaleDataTimer_Tick(object? sender, EventArgs e)
+    {
+        UpdateStaleDataIndicator();
+    }
+
+    private void UpdateStaleDataIndicator()
+    {
+        if (_lastRefreshed.HasValue)
+        {
+            var elapsed = DateTime.UtcNow - _lastRefreshed.Value;
+            LastRefreshedIndicator.Text = elapsed.TotalSeconds < 5
+                ? "Refreshed just now"
+                : elapsed.TotalMinutes < 1
+                    ? $"Refreshed {(int)elapsed.TotalSeconds}s ago"
+                    : $"Refreshed {(int)elapsed.TotalMinutes}m ago";
+        }
+
+        // Show archival warning if ArchiveService is currently running
+        if (ArchiveService.IsArchiving)
+        {
+            ArchivalWarning.Text = "⚠ Archival in progress";
+            ArchivalWarning.Visibility = Visibility.Visible;
+        }
+        else
+        {
+            ArchivalWarning.Visibility = Visibility.Collapsed;
+        }
+    }
+
+    #endregion
+
     #region Event Handlers
 
     private async void TimeRangeComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)

Lite/Services/ArchiveService.cs

@@ -30,6 +30,12 @@ public class ArchiveService
     private readonly ILogger<ArchiveService>? _logger;
     private static readonly SemaphoreSlim s_archiveLock = new(1, 1);
 
+    /// <summary>
+    /// Indicates whether an archival operation is currently in progress.
+    /// UI code can check this to warn users before dismiss or show a status indicator.
+    /// </summary>
+    public static bool IsArchiving { get; private set; }
+
     /* Tables eligible for archival with their time column.
        IMPORTANT: Every table with time-series data must be listed here,
        or it will grow unbounded and push the DB past the 512 MB reset threshold. */
@@ -88,6 +94,7 @@ public async Task ArchiveOldDataAsync(int hotDataDays = 7, int? hotDataHours = n
             return;
         }
 
+        IsArchiving = true;
         try
         {
         var cutoffDate = hotDataHours.HasValue
@@ -146,6 +153,7 @@ Archive views use glob (*_table.parquet) to pick up all files. */
         }
         finally
         {
+            IsArchiving = false;
             s_archiveLock.Release();
         }
     }
@@ -416,6 +424,7 @@ public async Task ArchiveAllAndResetAsync()
             return;
         }
 
+        IsArchiving = true;
         try
         {
             var timestamp = DateTime.UtcNow.ToString("yyyyMMdd_HHmm");
@@ -475,6 +484,7 @@ and only touches filesystem files — no contention with collectors. */
         }
         finally
         {
+            IsArchiving = false;
             s_archiveLock.Release();
         }
     }