Major x64 fixes and code modernization.
x64
- Fixed root cause of all x64 crashes: removed LONG_PTR/DWORD_PTR 32-bit redefinitions from stdafx.h
- Fixed 49 pointer truncation sites found via compiler-assisted audit (C4302/C4311/C4312)
- Added initialization guards for tree control and splitter window callbacks
- Widened event callback signatures to UINT_PTR for pointer-safe parameter passing
Code modernization
- Replaced 16 raw LPSTR string members with std::string in download property structs
- Added C++20 default member initializers (replaces ZeroMemory on structs)
- Removed destructive ZeroMemory calls on structs containing std::string
- Debug builds now link correct vcpkg debug libraries
Full Changelog: v1.0.2...v1.0.3