feat: optimize longitudinal ST profiles

ClumsyPilot/ParkrobTrajplanner/EMPlanner/Longitudinal/LongitudinalPlanner.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Threading;
+
+namespace MultiWheelC.TrajectoryPlanning.EMPlanner;
+
+/// <summary>Pure longitudinal planning facade that depends only on the solver-neutral IQpSolver boundary.</summary>
+public sealed class LongitudinalPlanner
+{
+    private readonly SequentialLongitudinalOptimizer _optimizer;
+
+    public LongitudinalPlanner(IQpSolver qpSolver)
+    {
+        _optimizer = new SequentialLongitudinalOptimizer(qpSolver ?? throw new ArgumentNullException(nameof(qpSolver)));
+    }
+
+    public LongitudinalPlanningResult Plan(LongitudinalPlanningInput input, CancellationToken cancellationToken)
+    {
+        return _optimizer.Optimize(input, cancellationToken);
+    }
+}