feat: add common WoW global constants for addon compatibility

Add frequently referenced WoW global constants that many addons check:
- MAX_TALENT_TABS, MAX_NUM_TALENTS
- BOOKTYPE_SPELL, BOOKTYPE_PET
- MAX_PARTY_MEMBERS, MAX_RAID_MEMBERS, MAX_ARENA_TEAMS
- INVSLOT_FIRST_EQUIPPED, INVSLOT_LAST_EQUIPPED
- NUM_BAG_SLOTS, NUM_BANKBAGSLOTS, CONTAINER_BAG_OFFSET
- MAX_SKILLLINE_TABS, TRADE_ENCHANT_SLOT

Prevents nil-reference errors when addons use these standard constants.

src/addons/lua_engine.cpp

@@ -3663,6 +3663,21 @@ void LuaEngine::registerCoreAPI() {
         "function GetShapeshiftFormInfo(index) return nil, nil, nil, nil end\n"
         // Pet action bar
         "NUM_PET_ACTION_SLOTS = 10\n"
+        // Common WoW constants used by many addons
+        "MAX_TALENT_TABS = 3\n"
+        "MAX_NUM_TALENTS = 100\n"
+        "BOOKTYPE_SPELL = 0\n"
+        "BOOKTYPE_PET = 1\n"
+        "MAX_PARTY_MEMBERS = 4\n"
+        "MAX_RAID_MEMBERS = 40\n"
+        "MAX_ARENA_TEAMS = 3\n"
+        "INVSLOT_FIRST_EQUIPPED = 1\n"
+        "INVSLOT_LAST_EQUIPPED = 19\n"
+        "NUM_BAG_SLOTS = 4\n"
+        "NUM_BANKBAGSLOTS = 7\n"
+        "CONTAINER_BAG_OFFSET = 0\n"
+        "MAX_SKILLLINE_TABS = 8\n"
+        "TRADE_ENCHANT_SLOT = 7\n"
         "function GetPetActionInfo(slot) return nil end\n"
         "function GetPetActionsUsable() return false end\n"
     );