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.API/Transactions/Webhook/Endpoint.cs

@@ -0,0 +1,41 @@
+namespace FiscalOS.API.Transactions.Webhook;
+
+internal static class Endpoint
+{
+  private const string Route = "/webhook";
+
+  public static RouteHandlerBuilder MapWebhookEndpoint(this RouteGroupBuilder groupBuilder)
+  {
+    return groupBuilder.MapPost(Route, HandleAsync);
+  }
+
+  private static async Task<IResult> HandleAsync(
+    [FromBody] WebhookBase request,
+    [FromServices] ILogger<Program> logger,
+    [FromServices] IAsyncQueue<SyncUpdatesQueueItem> queue,
+    CancellationToken ct
+  )
+  {
+    logger.LogInformation(
+      "Received {WebhookType} webhook with {WebhookCode} payload",
+      request.WebhookType,
+      request.WebhookCode
+    );
+
+    switch (request)
+    {
+      case SyncUpdatesAvailableWebhook webhook:
+        await queue.EnqueueAsync(new(webhook.ItemId), ct);
+        logger.LogInformation(
+          "Enqueued {WebhookType} webhook with {WebhookCode} payload",
+          request.WebhookType,
+          request.WebhookCode
+        );
+        break;
+      default:
+        break;
+    }
+
+    return Results.Ok();
+  }
+}