Add project files.

src/modules/Elsa.Alterations.Core/Contracts/IAlterationPlanScheduler.cs

@@ -0,0 +1,14 @@
+using Elsa.Alterations.Core.Models;
+
+namespace Elsa.Alterations.Core.Contracts;
+
+/// <summary>
+/// Scheduler for alteration plans.
+/// </summary>
+public interface IAlterationPlanScheduler
+{
+    /// <summary>
+    /// Submits an alteration plan for execution.
+    /// </summary>
+    Task<string> SubmitAsync(AlterationPlanParams planParams, CancellationToken cancellationToken = default);
+}