fix: keep exact snapping, source drawing data and adaptive options layout

Resolve curve intersections through cadkernel, retain empty exact results, gather analytic candidates independently of tessellation, and bound material uploads. Preserve large MINSERT data while limiting rendering work; remove obsolete review narratives.

src/scene/group_layer.rs

@@ -183,14 +183,6 @@ impl Scene {
         handles: &[Handle],
     ) -> HashSet<Handle> {
         let mut expanded: HashSet<Handle> = handles.iter().copied().collect();
-        // Asked the other way round, this was quadratic: for every group, scan
-        // every selected handle, and `Group::contains` is a linear scan of the
-        // group's own entity list. A box selection of 185 096 entities spent
-        // seconds here.
-        //
-        // The membership set is the *input* handles, not `expanded` — a group
-        // must match because something the user selected is in it, not because
-        // an earlier group already contributed one of its members.
         let wanted: HashSet<Handle> = handles.iter().copied().collect();
         for obj in self.document.objects.values() {
             if let ObjectType::Group(g) = obj {
@@ -218,10 +210,6 @@ mod group_expansion_tests {
     use super::*;
     use crate::scene::Scene;
 
-    /// Selecting one member of a selectable group selects the whole group, and
-    /// a group nobody touched stays out. The lookup was inverted for speed —
-    /// it asked every group about every selected handle, and `Group::contains`
-    /// scans the group's own list — so the answer has to be shown unchanged.
     #[test]
     fn group_expansion_pulls_in_siblings_and_nothing_else() {
         use acadrust::entities::{EntityType, Line};