- Updated all CMakeLists.txt files to use Qt6:: libraries
- Added LtsFileDialog submodule (copied from qt5-before)
- Added LtsReportDisplay submodule (copied from qt5-before)
- Enabled both submodules in main Viewer CMakeLists.txt
- Qt5::Core/Widgets → Qt6::Core/Widgets in all Viewer modules
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>