Switch Item.template and MobLoot to CObjectTemplate

Item.template is now the cache template from CObjectTemplate.lookup
instead of the legacy DB ItemTemplate, so item.template.cacheTemplate.X
becomes item.template.X. MobLoot, LootManager, ItemManager.isTwoHanded/
isShield and CombatManager.getSwingAnimation take a CObjectTemplate.

No value changes: every getter already read the cache template through
the bridge, and the lookup resolves the same 7586 ids as
static_item_templates with the same item_type (offline parity p17.py,
0 differences).

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

src/engine/net/client/handlers/PlaceAssetMsgHandler.java

@@ -357,7 +357,7 @@ public class PlaceAssetMsgHandler extends AbstractClientMsgHandler {
         Item contract = null;
 
         for (Item inventoryItem : playerCharacter.getInventory()) {
-            if (inventoryItem.template.cacheTemplate.getItemType().equals(ItemType.DEED) &&
+            if (inventoryItem.template.getItemType().equals(ItemType.DEED) &&
                     DeedTemplate._deeds.get(inventoryItem.templateID).deed_structure_id == buildingList.getBlueprintUUID()) {
                 contract = inventoryItem;
                 break;