Move the vendor mod table off the legacy item template

LOAD_TEMPLATE_MODTABLES now returns a templateID -> modTable map that
ForgeManager owns (vendorModTables). ForgeManager.forgeItem, WorkOrder
validation and the ManageNPCMsg forge item list read it through
ForgeManager.getVendorModTable(), and ItemTemplate.modTable is removed.

Values are unchanged: static_vendor_items has 5089 rows, one per
templateID, all present in static_item_templates, modTable 0-30.
Templates not in the table still read 0. The old loader stopped at the
first templateID missing from ItemTemplate.templates; there are none.
No comparator added or removed.

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

src/engine/objects/ItemTemplate.java

@@ -101,7 +101,6 @@ public class ItemTemplate {
     // engine.parsers.objects.RuneTemplate keeps the full list.
     public final HashMap<String, int[]> item_power_action = new HashMap<>();
     public final HashMap<mbEnums.ResourceType, Integer> item_resource_cost = new HashMap<>();
-    public int modTable;
     public int deed_type;
     public int deed_furniture_id;
     public int deed_target_id;