move ecs related code to own folder

src/lib/ecs/component/MovementIntentComponent.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <QVector2D>
+
+// A ship-behavior system writes this each tick before movement runs; the
+// highest-priority write wins. Priority order is fixed globally — see
+// architecture.md "Movement Arbitration".
+struct MovementIntentComponent
+{
+    int priority;
+    QVector2D target;
+};