Entity: an equipped item keeps the hardpoint it occupies

The placement rule (HardpointAt) already finds the one hardpoint an item lies
in at equip; TryEquip threw that answer away and eighteen readers recomputed it
from the item's origin cell, which need not lie in the hardpoint (Soul's
scenarios batch-4 P30). EquippedItem.Hardpoint now carries the answer, null for
Tool gear and the hull, and every origin-cell lookup reads it instead:
FireControl.ArcFor, the eleven weapon managers, EntityInstance, ShipInstance
and ActionGameManager's articulation grouping. Entity.Hardpoints[,] stays the
per-cell map for armour and display.

TryFindSpace's hardpoint search tries every origin the fit rule can accept,
including ones up and left of the hardpoint, so a design whose shape lacks its
origin cell is found wherever ItemFits would place it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Assets/Scripts/Gameplay/Weapons/ProjectileManager.cs

@@ -11,7 +11,7 @@ public class ProjectileManager : InstantWeaponEffectManager
     public override void Fire(InstantWeapon weapon, EquippedItem item, EntityInstance source, EntityInstance target, int shotId)
     {
         var p = ProjectilePrototype.Instantiate<Projectile>();
-        var hp = source.Entity.Hardpoints[item.Position.x, item.Position.y];
+        var hp = item.Hardpoint;
         var barrel = source.GetBarrel(hp);
         var angle = weapon.Spread / 2;
         p.ShotId = shotId;