Registers the upstream ip7z/7zip repository as a git submodule at
versions/26.01, checked out at tag 26.01 (commit 8c63d71).
This provides the 7-Zip 26.01 vendor source tree for both the Windows
(MSBuild/vcxproj) and Linux (MinGW cross-compilation) builds.
- Implemented plugin API in `pluginapi.cpp` and `pluginapi.h` for NSIS integration.
- Added resource files `resource.h` and `resource.rc` for versioning and resource management.
- Created `ExtractCallbackConsole` class to handle extraction progress and user input.
- Developed main extraction logic in `Main.cpp` and `MainAr.cpp` for handling archives.
- Introduced user input utilities in `UserInputUtils2.cpp` and `UserInputUtils2.h` for password handling and user prompts.
- Added break signal handling in `NSISBreak.cpp` and `NSISBreak.h` for graceful interruption of extraction processes.
- Included standard header `StdAfx.h` for precompiled headers and common includes.
Simone