Remove Qt6 apt packages - use aqt install-qt only
Removed 13 Qt6 packages from apt installation:
- libqt6core6, libqt6gui6, libqt6widgets6
- libqt6sql6, libqt6sql6-psql, libqt6test6
- qt6-base-dev, qt6-l10n-tools
- qt6-serialport-dev, qt6-svg-dev
- qt6-tools-dev-tools, qt6-tools-dev
- qt6-websockets-dev
Qt installation now uses ONLY aqt install-qt (lines 424-428)
System dependencies remain: build-essential, cmake, ninja-build, git, python3-pip, boost, kf6texttemplate, gtest/gmock, postgresql, vlc, ssl, xml, xerces
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>