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/common/Win32Crt.h

@@ -12,6 +12,14 @@
 #if !defined(_WIN32)
 #include <strings.h>
 
+#include "Win32MinMax.h"
+
+// mmsystem.h
+#ifndef MAKEFOURCC
+#define MAKEFOURCC(ch0, ch1, ch2, ch3) \
+	((DWORD)(BYTE)(ch0) | ((DWORD)(BYTE)(ch1) << 8) | ((DWORD)(BYTE)(ch2) << 16) | ((DWORD)(BYTE)(ch3) << 24))
+#endif
+
 #define ZeroMemory(dst, len) std::memset((dst), 0, (len))
 #define FillMemory(dst, len, fill) std::memset((dst), (fill), (len))
 #define CopyMemory(dst, src, len) std::memcpy((dst), (src), (len))
@@ -41,6 +49,12 @@ int _snprintf(char* buf, size_t count, const char* fmt, ...)
 #endif
 	;
 
+// kernel32 file-system calls (ANSI). CreateDirectory ignores the security attributes; _access takes
+// the MSVC modes 0 (exists), 2 (write), 4 (read), 6 (read/write).
+BOOL CreateDirectory(LPCSTR path, void* security_attributes);
+BOOL DeleteFile(LPCSTR path);
+int _access(const char* path, int mode);
+
 // winmm `timeGetTime`: milliseconds since system start, wrapping at 2^32.
 DWORD timeGetTime();
 DWORD GetTickCount();