make repair ships standby with rest of fleet if there is no one to repair (instead of advancing towards the enemy stations)

src/lib/ecs/system/ai/StandbyEvaluator.h

@@ -0,0 +1,12 @@
+#pragma once
+
+class EntityAdmin;
+
+// Constant low-priority fallback for repair-capable ships: gives a fixed score
+// just above Advance so a repair ship with nothing more urgent to do holds with
+// its fleet (StandbyExecutor) instead of charging the enemy.
+class StandbyEvaluator
+{
+public:
+    void evaluate(EntityAdmin& admin);
+};