Turn src/ifcviewer into libIfcViewer.so holding the rendering engine +
geometry pipeline (ViewportWindow, GeometryStreamer, BvhAccel,
InstancedGeometry, SidecarCache, LodBuilder, AppSettings). Move the
existing UI shell (MainWindow, SettingsWindow, main.cpp) into
src/ifcviewer-full as the IfcViewerFull executable. Add a new
src/ifcviewer-minimal target with a MinimalWindow that hosts only the
viewport and reuses the sidecar fast-path for benchmark/debug runs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Dion Moult