feat(26.01): add bundle wrapper directory with NSIS sources and vendor symlinks

7-Zip 26.01 (ip7z/7zip) never shipped NSIS plugin sources, so they live in
a separate bundle directory (versions/26.01-bundle/) that mirrors the layout
expected by the shared overlay makefile and by MSBuild.

Bundle contents:
- CPP/7zip/Bundles/Nsis7z/: NSIS plugin wrapper sources (nsis7z.cpp,
  pluginapi.cpp, api.h, resource.rc, StdAfx.h, …) and the Windows build
  project file (Nsis7z_vs2026.vcxproj, adapted from versions/26.00/).
  The vcxproj references the vendor submodule tree via relative paths
  (../../../../../26.01/…), keeping the submodule pristine.
- CPP/7zip/UI/NSIS/: NSIS UI adapter sources (Main.cpp, MainAr.cpp,
  NSISBreak.cpp, ExtractCallbackConsole.cpp, UserInputUtils2.cpp and
  corresponding headers), copied from versions/26.00/.
- CPP/7zip/LzmaDec_gcc.mak: forwarding stub; GNU make resolves relative
  `include` paths against the CWD, so when make runs from Bundles/Nsis7z
  the upstream Arc_gcc.mak's `include ../../LzmaDec_gcc.mak` lands here.
  The stub re-includes the real file via $(VENDOR_7ZIP).
- Symlinks (C, Asm, CPP/7zip/*, CPP/Common, CPP/Windows, …) pointing into
  the versions/26.01 submodule.  These are required because the vendor
  makefile uses CWD-relative source paths (../../../../C/…, ../../Common/…).
  tools/linux/setup_26_01_bundle_symlinks.py recreates them if needed.

versions/26.01-bundle/CPP/7zip/UI/NSIS/ExtractCallbackConsole.h

@@ -0,0 +1,98 @@
+// ExtractCallbackConsole.h
+// NSIS version adapted for 7-Zip 25.01 API
+
+#ifndef __EXTRACTCALLBACKCONSOLE_H
+#define __EXTRACTCALLBACKCONSOLE_H
+
+#include "Common/MyCom.h"
+#include "Common/MyString.h"
+#include "Common/StdOutStream.h"
+#include "../../Common/FileStreams.h"
+#include "../../IPassword.h"
+#include "../../Archive/IArchive.h"
+#include "../Common/ArchiveExtractCallback.h"
+#include "../Console/OpenCallbackConsole.h"
+
+typedef void (*ExtractProgressHandler)(UInt64 completedSize, UInt64 totalSize);
+typedef void (*ExtractProgressWithFileHandler)(UInt64 completedSize, UInt64 totalSize, const wchar_t *fileName);
+
+class CExtractCallbackConsole Z7_final:
+  public IFolderArchiveExtractCallback,
+  public IExtractCallbackUI,
+#ifndef Z7_NO_CRYPTO
+  public ICryptoGetTextPassword,
+#endif
+  public COpenCallbackConsole,
+  public CMyUnknownImp
+{
+  Z7_COM_QI_BEGIN2(IFolderArchiveExtractCallback)
+#ifndef Z7_NO_CRYPTO
+  Z7_COM_QI_ENTRY(ICryptoGetTextPassword)
+#endif
+  Z7_COM_QI_END
+  Z7_COM_ADDREF_RELEASE
+
+  // IProgress
+  Z7_IFACE_COM7_IMP(IProgress)
+  
+  // IFolderArchiveExtractCallback
+  Z7_IFACE_COM7_IMP(IFolderArchiveExtractCallback)
+
+  // IExtractCallbackUI (non-COM interface)
+  Z7_IFACE_IMP(IExtractCallbackUI)
+
+#ifndef Z7_NO_CRYPTO
+  Z7_IFACE_COM7_IMP(ICryptoGetTextPassword)
+#endif
+
+public:
+#ifndef Z7_NO_CRYPTO
+  bool PasswordIsDefined;
+  UString Password;
+#endif
+  
+  UInt64 NumArchives;
+  UInt64 NumArchiveErrors;
+  UInt64 NumFileErrors;
+  UInt64 NumFileErrorsInCurrentArchive;
+
+  CStdOutStream *OutStream;
+
+  UInt64 totalSize, completedSize, lastVal;
+
+  ExtractProgressHandler ProgressHandler;
+  ExtractProgressWithFileHandler ProgressWithFileHandler;
+  UString CurrentFileName;
+
+  CExtractCallbackConsole():
+    PasswordIsDefined(false),
+    NumArchives(0),
+    NumArchiveErrors(0),
+    NumFileErrors(0),
+    NumFileErrorsInCurrentArchive(0),
+    OutStream(NULL),
+    totalSize((UInt64)(Int64)-1),
+    completedSize(0),
+    lastVal(0),
+    ProgressHandler(NULL),
+    ProgressWithFileHandler(NULL)
+  {}
+
+  void Init()
+  {
+    NumArchives = 0;
+    NumArchiveErrors = 0;
+    NumFileErrors = 0;
+    NumFileErrorsInCurrentArchive = 0;
+
+    totalSize = (UInt64)(Int64)-1;
+    completedSize = 0;
+    lastVal = 0;
+    ProgressHandler = NULL;
+    ProgressWithFileHandler = NULL;
+  }
+
+  void UpdateProgress();
+};
+
+#endif