refactor AI system

src/lib/ecs/system/SalvagerSystem.h

@@ -0,0 +1,19 @@
+#pragma once
+
+class BuildingSystem;
+class EntityAdmin;
+class ScrapSystem;
+
+// World-mutation system for salvage modules: collects scrap into cargo and
+// delivers full cargo at a SalvageBay. Runs every tick, independent of which
+// behavior the AiSystem selected.
+class SalvagerSystem
+{
+public:
+    explicit SalvagerSystem(EntityAdmin& admin);
+
+    void tick(ScrapSystem& scraps, BuildingSystem& buildings);
+
+private:
+    EntityAdmin& m_admin;
+};