feat: add Plaid transaction handling and async queue processing

- introduced new migration to add Cursor column to AccountMetadata.
- updated AppDbContext model snapshot to reflect changes in the database schema.
- implemented async queue processing with ChannelAsyncQueue and AsyncQueueHostedService.
- created Plaid transaction handlers for added, modified, and removed transactions.
- developed PlaidTransactionService and PlaidTransactionSyncer for syncing transactions.
- added SyncUpdatesProcessor to handle sync updates from Plaid.
- updated tests to accommodate changes in institution and account metadata handling.

src/FiscalOS.Infra/Transactions/Plaid/PlaidAddedTransactionHandler.cs

@@ -0,0 +1,54 @@
+using Account = FiscalOS.Core.Accounts.Account;
+using Transaction = FiscalOS.Core.Transactions.Transaction;
+
+namespace FiscalOS.Infra.Transactions.Plaid;
+
+internal interface IPlaidAddedTransactionHandler
+{
+  void Handle(Account account, IEnumerable<Going.Plaid.Entity.Transaction> added);
+}
+
+internal sealed class PlaidAddedTransactionHandler : IPlaidAddedTransactionHandler
+{
+  private readonly ILogger<PlaidAddedTransactionHandler> _logger;
+
+  private PlaidAddedTransactionHandler(ILogger<PlaidAddedTransactionHandler> logger)
+  {
+    _logger = logger;
+  }
+
+  public static PlaidAddedTransactionHandler From(IServiceProvider serviceProvider)
+  {
+    return new(
+      serviceProvider.GetRequiredService<ILogger<PlaidAddedTransactionHandler>>()
+    );
+  }
+
+  public void Handle(Account account, IEnumerable<Going.Plaid.Entity.Transaction> added)
+  {
+    foreach (var addedTransaction in added)
+    {
+      if (addedTransaction.Pending.GetValueOrDefault())
+      {
+        _logger.LogInformation(
+          "Skipping pending transaction {TransactionId} for account {AccountId} as it has not been posted yet",
+          addedTransaction.TransactionId,
+          account.Id
+        );
+        continue;
+      }
+
+      var transactionMetadata = PlaidTransactionMetadata.From(addedTransaction.TransactionId);
+      var transaction = Transaction.From(
+        account.UserId,
+        account.Id,
+        addedTransaction.MerchantName,
+        addedTransaction.OriginalDescription,
+        addedTransaction.Amount,
+        addedTransaction.Datetime,
+        transactionMetadata
+      );
+      account.AddTransaction(transaction);
+    }
+  }
+}