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.cpp

@@ -0,0 +1,59 @@
+#include "StdAfx.h"
+#include "EterPackCursor.h"
+#include "Inline.h"
+
+CEterPackCursor::CEterPackCursor(CEterPack* pack) : m_pPack(pack), m_pData(NULL), m_ReadPoint(0)
+{
+}
+
+CEterPackCursor::~CEterPackCursor()
+{
+	Close();
+}
+
+bool CEterPackCursor::Open(const char* filename)
+{
+	assert(m_pPack != NULL);
+	
+	char tmpFilename[MAX_PATH + 1];
+	strncpy(tmpFilename, filename, MAX_PATH);
+	inlineConvertPackFilename(tmpFilename);
+	
+	if (!m_pPack->Get(m_file, tmpFilename, &m_pData))
+		return false;
+	
+	return true;
+}
+
+void CEterPackCursor::Close()
+{
+	m_file.Destroy();
+	m_pData = NULL;
+	m_ReadPoint = 0;
+}
+
+void CEterPackCursor::Seek(long offset)
+{
+	m_ReadPoint = max(0, min(Size(), offset));
+}
+
+bool CEterPackCursor::Read(LPVOID data, long size)
+{
+	if (m_file.IsNull())
+		return false;
+	
+	if (m_ReadPoint + size > Size())
+		return false;
+	
+	memcpy(data, (char*) m_pData + m_ReadPoint, size);
+	m_ReadPoint += size;
+	return true;
+}
+
+long CEterPackCursor::Size()
+{
+	if (m_file.IsNull())
+		return 0;
+	
+	return m_file.Size();
+}