feat: add Serilog with Console and Seq sinks, log TransactionBehavior

- Add Serilog.AspNetCore + Sinks.Console + Sinks.Seq to Api
- Add Serilog.Extensions.Hosting + Sinks.Console + Sinks.Seq to Worker
- Add Microsoft.Extensions.Logging.Abstractions to Services
- TransactionBehavior logs handler name, elapsed time, and errors

Ref: IT-628

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

HrynCo.NotificationService.Services/Behaviors/TransactionBehavior.cs

@@ -1,5 +1,7 @@
+using System.Diagnostics;
 using HrynCo.NotificationService.DAL.Abstract;
 using MediatR;
+using Microsoft.Extensions.Logging;
 
 namespace HrynCo.NotificationService.Services.Behaviors;
 
@@ -7,19 +9,36 @@ public class TransactionBehavior<TRequest, TResponse> : IPipelineBehavior<TReque
     where TRequest : notnull
 {
     private readonly IUnitOfWork _unitOfWork;
+    private readonly ILogger<TransactionBehavior<TRequest, TResponse>> _logger;
 
-    public TransactionBehavior(IUnitOfWork unitOfWork)
+    public TransactionBehavior(IUnitOfWork unitOfWork, ILogger<TransactionBehavior<TRequest, TResponse>> logger)
     {
         _unitOfWork = unitOfWork;
+        _logger = logger;
     }
 
-    public Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
+    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
     {
-        return _unitOfWork.ExecuteInTransactionAsync(async () =>
+        string handlerName = typeof(TRequest).Name;
+        _logger.LogDebug("Handling {Handler}", handlerName);
+
+        Stopwatch sw = Stopwatch.StartNew();
+        try
         {
-            TResponse result = await next();
-            await _unitOfWork.SaveChangesAsync(cancellationToken);
+            TResponse result = await _unitOfWork.ExecuteInTransactionAsync(async () =>
+            {
+                TResponse response = await next();
+                await _unitOfWork.SaveChangesAsync(cancellationToken);
+                return response;
+            });
+
+            _logger.LogDebug("Handled {Handler} in {ElapsedMs}ms", handlerName, sw.ElapsedMilliseconds);
             return result;
-        });
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Handler {Handler} failed after {ElapsedMs}ms", handlerName, sw.ElapsedMilliseconds);
+            throw;
+        }
     }
-}
+}