feat: implement transaction handling and add integration tests for Plaid transaction handlers

tests/FiscalOS.Infra.Tests/Unit/PlaidTransactionSyncerTests.cs

@@ -0,0 +1,13 @@
+namespace FiscalOS.Infra.Tests.Unit;
+
+public class PlaidTransactionSyncerTests
+{
+  private readonly Mock<ILogger<PlaidTransactionSyncer>> _mockSyncer = new();
+  private 
+  private readonly PlaidTransactionSyncer _sut;
+
+  public PlaidTransactionSyncer()
+  {
+    _sut = PlaidTransactionSyncer.From();
+  }
+}