Add build system version detection as a fallback in GetCurrentVersion():
- Include common/scm_rev.h to access build version information
- Use Common::g_build_version when version.txt doesn't exist
- Automatically create version.txt with build version for future use
- Update comments to clarify version resolution priority
This ensures the updater can properly detect the current application
version even when version.txt hasn't been created yet, while maintaining
the existing priority system for version detection.
Signed-off-by: Zephyron <zephyron@citron-emu.org>
25e8c0539c