port: ItemData, ItemManager, PythonNonPlayer + LoadLocaleData (batch 2 P3-a)

Verbatim 40250 GameLib ItemData/ItemManager and UserInterface
PythonNonPlayer(+Module) replace their pending stand-ins and the
nonplayer module stub. LoadLocaleData's body moves into the platform
CPythonApplication stand-in, so the select phase loads item_proto and
mob_proto; CPythonSkill is still pending, so it returns false after the
tables load. login_flow checks item 19 (Sword+9) and mob 101 (Wild Dog),
offline and live.

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

extension/src/platform/pending/UserInterface/PythonSkill.cpp

@@ -191,3 +191,20 @@ auto CPythonSkill::SSkillData::GetType() const -> BYTE
 	MT_PLATFORM_STUB();
 	return mt_platform_stub_return<BYTE>();
 }
+
+auto CPythonSkill::Destroy() -> void
+{
+	MT_PLATFORM_STUB();
+}
+
+auto CPythonSkill::RegisterSkillTable(const char *) -> bool
+{
+	MT_PLATFORM_STUB();
+	return mt_platform_stub_return<bool>();
+}
+
+auto CPythonSkill::RegisterSkillDesc(const char *) -> bool
+{
+	MT_PLATFORM_STUB();
+	return mt_platform_stub_return<bool>();
+}