port(2P step 3a/3b): stdlib on sys.path + the pack module

step 3a — 标准库:
  tools/py_embed/make_stdlib_zip.py packs the vendored Lib/ into
  <build>/python27.zip (397 modules, 6876547 bytes, ZIP_STORED — the zlib
  module is trimmed out of our CPython, so zipimport cannot inflate).
  The mtpython_stdlib target builds it; py_embed_test and the launcher test
  both run against it.
  platform/ScriptLib/PythonHost sets the embedding flags before
  Py_Initialize and, after it, puts the zip on sys.path and re-registers
  encodings.search_function with codecs — 2.7 builds the codec registry
  once, at startup, so replacing sys.path afterwards needs it back.

step 3b — pack 模块:
  UserInterface/PythonPackModule.cpp copied verbatim; packExist/packGet/
  initpack read root/ and uiscript/ through CEterPackManager, i.e. through
  asset_io. The CHINA_CRYPT_KEY block in that unit is CAccountConnector's
  and is kept #if 0 until the login slice (2V1). UserInterface/StdAfx.h is
  a documented partial mirror — the original is the whole client's PCH.

The launcher test now runs initpack() as RunMainScript does (its first
line), reads system.py / uiscript / locale text back out of the packs, and
confirms cp1252 decoding works off the zip. system.py still stops at
"No module named app" — the C++ modules are the 2V0 slice.

gates: port_map.py check 0 errors · key leak check 8/8 none · macOS ctest
27/27 · android + ios port_platform compile clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

extension/src/port/UserInterface/StdAfx.h

@@ -0,0 +1,27 @@
+#pragma once
+// PORT: a partial mirror of 40250 UserInterface/StdAfx.h.
+//
+// The original is the precompiled header of the whole client: it includes eterLib, eterPythonLib,
+// gameLib, scriptLib, milesLib, EffectLib, PRTerrainLib and SpeedTreeLib's StdAfx.h, plus <dshow.h>
+// and <qedit.h>, Locale.h and GameType.h. Only scriptLib exists in the port tree today, so this file
+// carries the part the ported units actually use and grows with the 2V slices that bring the rest
+// (docs/PORT-PLAN.md 批次 2V0-2V3).
+
+#include "../ScriptLib/StdAfx.h"
+
+#define APP_NAME	"Metin 2"
+
+enum
+{
+	POINT_MAX_NUM = 255,
+	CHARACTER_NAME_MAX_LEN = 24,
+#if defined(LOCALE_SERVICE_JAPAN)
+	PLAYER_NAME_MAX_LEN = 16,
+#else
+	PLAYER_NAME_MAX_LEN = 12,
+#endif
+};
+
+// The Python module initializers RunMainScript calls, each defined in its own Python*Module.cpp.
+// Listed here as 40250 lists them; only the ported ones are defined.
+void initpack();