port: CPythonSkill + skill module + EterBase/Poly (1:1 40250)

Copy PythonSkill.cpp and the EterBase/Poly formula parser verbatim, drop the
pending stand-in and the skill module stub, register initskill() after
initfly() and build CPythonSkill in m_pySkill's place. LoadLocaleData now
loads skilldesc/skilltable. Skill and item icon handles go through
Py_BuildPointer/PyTuple_GetPointer (ILP32 ints truncate 64-bit pointers).

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

extension/src/platform/ScriptLib/PythonBoot.cpp

@@ -27,6 +27,7 @@
 #include "UserInterface/PythonMiniMap.h"
 #include "UserInterface/PythonEventManager.h"
 #include "UserInterface/PythonBackground.h"
+#include "UserInterface/PythonSkill.h"
 #include "UserInterface/PythonQuest.h"
 #include "UserInterface/PythonMessenger.h"
 #include "UserInterface/PythonSafeBox.h"
@@ -117,6 +118,7 @@ struct GameSingletons
 	CPythonMiniMap pyMiniMap;
 	CPythonEventManager pyEventManager;
 	CPythonBackground pyBackground;
+	CPythonSkill pySkill;
 	CPythonQuest pyQuest;
 	CPythonMessenger pyManager;
 	CPythonSafeBox pySafeBox;
@@ -356,6 +358,7 @@ bool run_main_script_body(const char* lpCmdLine, std::string* error)
 	initMiniMap();
 	initeffect();
 	initfly();
+	initskill();
 	initServerStateChecker();
 	init_2v0_gameplay_stubs();