move ecs related code to own folder

src/lib/ecs/system/ShipSystem.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <optional>
+#include <string>
+
+#include <QVector2D>
+
+#include "GameConfig.h"
+#include "ShipLayout.h"
+
+#include "entt/entity/entity.hpp"
+
+class EntityAdmin;
+
+class ShipSystem
+{
+public:
+    ShipSystem(const GameConfig& config, EntityAdmin& admin);
+
+    entt::entity spawn(const std::string& schematicId, int level, QVector2D position,
+                       bool isEnemy = false,
+                       const std::optional<ShipLayoutConfig>& layout = std::nullopt);
+    void despawn(entt::entity entity);
+
+    // Reset all movement intents to priority 0 before behavior systems run.
+    void clearMovementIntents();
+
+    // Set the rally point that newly spawned player combat ships will loiter at.
+    void setRallyPoint(QVector2D point);
+
+    // Release all gathered player combat ships to advance toward the enemy.
+    void triggerRallyDeparture();
+
+private:
+    const ShipDef*   findShipDef(const std::string& schematicId) const;
+    const ModuleDef* findModuleDef(const std::string& id) const;
+
+    const GameConfig& m_config;
+    EntityAdmin&      m_admin;
+    QVector2D         m_rallyPoint;
+};