Cache canAttackTarget per template in DefenseArmy.assignUnit

For a foe which is not capturable, allowCapture has no effect and the
result of canAttackTarget only depends on the template of the unit.
Cache it in the foe info, which is rebuilt each turn.

binaries/data/mods/public/simulation/ai/petra/defenseArmy.js

@@ -29,9 +29,9 @@ function getFoeInfo(gameState, foeEntities)
 			if (orderData && orderData.length && orderData[0].target)
 				attackTarget = orderData[0].target;
 		}
-		// "heavy" and "access" are filled lazily.
+		// "heavy", "access" and the entries of "canAttack" are filled lazily.
 		info.push({ "id": id, "ent": eEnt, "position": position, "attackTarget": attackTarget,
-			"heavy": undefined, "access": undefined });
+			"capturable": eEnt.isCapturable(), "canAttack": new Map(), "heavy": undefined, "access": undefined });
 	}
 	return info;
 }
@@ -346,6 +346,7 @@ export class DefenseArmy
 		const pos = ent.position();
 		if (!pos)
 			return false;
+		const template = ent.templateName();
 
 		// try to return its resources, and if any, the attack order will be queued
 		const queued = returnResources(gameState, ent);
@@ -359,7 +360,15 @@ export class DefenseArmy
 		for (const foe of this.foeInfo)
 		{
 			const eEnt = foe.ent;
-			if (!ent.canAttackTarget(eEnt, allowCapture(gameState, ent, eEnt)))
+			// For a foe which is not capturable, allowCapture has no effect, so the result only depends on the template.
+			let canAttack = foe.canAttack.get(template);
+			if (canAttack === undefined)
+			{
+				canAttack = ent.canAttackTarget(eEnt, allowCapture(gameState, ent, eEnt));
+				if (!foe.capturable)
+					foe.canAttack.set(template, canAttack);
+			}
+			if (!canAttack)
 				continue;
 
 			if (foe.attackTarget === entID)