Add Telegram bot integration for real-time alert notifications

- Implemented ITelegramNotificationService and TelegramNotificationService for sending alerts via Telegram.
- Updated MonitoringSettings to include Telegram configuration options.
- Enhanced AlertService to send alerts and resolutions through Telegram.
- Added API endpoints for checking Telegram status and sending test alerts.
- Updated README and TELEGRAM_SETUP.md with setup instructions and features.
- Included example configuration in appsettings.telegram.example.json.

Services/AlertService.cs

@@ -21,6 +21,7 @@ namespace ResourceMonitorService.Services
     {
         private readonly ILogger<AlertService> _logger;
         private readonly MonitoringSettings _settings;
+        private readonly ITelegramNotificationService _telegramService;
         private readonly ConcurrentDictionary<string, Alert> _activeAlerts;
         private readonly ConcurrentQueue<Alert> _alertHistory;
         private readonly Dictionary<string, DateTime> _lastAlertTime;
@@ -29,10 +30,11 @@ namespace ResourceMonitorService.Services
         public event EventHandler<Alert>? AlertTriggered;
         public event EventHandler<Alert>? AlertResolved;
 
-        public AlertService(ILogger<AlertService> logger, IOptions<MonitoringSettings> settings)
+        public AlertService(ILogger<AlertService> logger, IOptions<MonitoringSettings> settings, ITelegramNotificationService telegramService)
         {
             _logger = logger;
             _settings = settings.Value;
+            _telegramService = telegramService;
             _activeAlerts = new ConcurrentDictionary<string, Alert>();
             _alertHistory = new ConcurrentQueue<Alert>();
             _lastAlertTime = new Dictionary<string, DateTime>();
@@ -183,6 +185,19 @@ namespace ResourceMonitorService.Services
 
                 _logger.LogWarning("Alert triggered: {Message}", alert.Message);
                 AlertTriggered?.Invoke(this, alert);
+
+                // Send Telegram notification
+                _ = Task.Run(async () =>
+                {
+                    try
+                    {
+                        await _telegramService.SendAlertAsync(alert);
+                    }
+                    catch (Exception ex)
+                    {
+                        _logger.LogError(ex, "Failed to send Telegram alert notification");
+                    }
+                });
             }
             else
             {
@@ -264,6 +279,19 @@ namespace ResourceMonitorService.Services
                     
                     _logger.LogInformation("Alert resolved: {Message}", resolvedAlert.Message);
                     AlertResolved?.Invoke(this, resolvedAlert);
+
+                    // Send Telegram resolution notification
+                    _ = Task.Run(async () =>
+                    {
+                        try
+                        {
+                            await _telegramService.SendAlertResolvedAsync(resolvedAlert);
+                        }
+                        catch (Exception ex)
+                        {
+                            _logger.LogError(ex, "Failed to send Telegram resolution notification");
+                        }
+                    });
                 }
             }
         }