Export the current 3D view as 2D DXF with optional hidden lines (#1449)

Adds File > Export > Current View as DXF: the visible bodies projected from the current camera onto 2D LINE/LWPOLYLINE entities, with hidden edges omitted or dashed.

Co-authored-by: cronos <19868002+crono2250@users.noreply.github.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/ui-egui/src/lib.rs

@@ -35,6 +35,7 @@ pub mod dialogs_save_mesh;
 pub mod dialogs_sheet;
 pub mod dialogs_surface;
 pub mod dialogs_sweep;
+pub mod dialogs_view_dxf;
 pub mod dim_view;
 #[cfg(test)]
 mod dimension_create_ui_tests;