port 2D step 5a: EterPack/EterPackManager + EterBase file units against the real 40250 packs

- Mirror copies: EterPack (EterPack, EterPackManager, EterPackCursor, CSHybridCrypt policy, Inline.h)
  and EterBase logic units tea/lzo/Timer/Stl/Random, with PORT-tagged width fixes (LONG index
  fields, static_assert(sizeof(TEterPackIndex) == 192), tea_word = Win32 unsigned long).
- TEA pack keys are extracted from the reference EterPack.cpp at configure time into
  build/.../EterPackKeys.generated.h; nothing key-bearing is tracked.
- Platform EterBase: FileBase (stdio, case-insensitive fallback), MappedFile (mmap /
  MapViewOfFile), CRC32, Debug, Utils StringPath/StringLowers.
- Win32Crt: CreateDirectory/DeleteFile/_access/MAKEFOURCC; Win32MinMax.h min/max (force-included
  on MinGW, whose windows.h omits them in C++).
- tests/port_eterpack_test: registers pack/Index like PackInitialize and checks 119
  registrations / 103 packs + root / 54891 entries / 52609 paths / 2282 overrides with
  first-registered-wins, and that exactly the 4 short-layout SECURITY files fail to load.
- 2R count corrected (136 -> 119 registrations, 103 distinct packs + root).

Not runtime-reachable yet (asset_io pack backend is step 5b), so port-map statuses stay TODO.
port_gate: macos/android/ios/windows PASS.

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

extension/src/port/EterPack/EterPackCursor.h

@@ -0,0 +1,25 @@
+#ifndef __INC_ETERPACKCURSOR_H__
+#define __INC_ETERPACKCURSOR_H__
+
+#include "EterPack.h"
+
+class CEterPackCursor
+{
+	public:
+		CEterPackCursor(CEterPack * pack);
+		~CEterPackCursor();
+
+		bool		Open(const char* filename);
+		void		Close();
+		void		Seek(long offset);
+		bool		Read(LPVOID data, long size);
+		long		Size();
+
+	private:
+		CEterPack * m_pPack;
+		CMappedFile m_file;
+		LPCVOID 	m_pData;
+		long		m_ReadPoint;
+};
+
+#endif