refactor(scene): group modules into role-based subfolders

Move the 30 flat modules under src/scene/ into six folders by role:
convert (entity→geometry), text (fonts/shaping), model (render models),
pick (hit-test/selection/grips/xclip), view (camera/transform/render),
cache (block + property caches). pipeline/ is unchanged.

Full path migration — all `scene::X` references become
`scene::<group>::X`, no compatibility re-exports. render.rs items that
were `pub(super)` (parent was scene) become `pub(in crate::scene)` to
keep their original scene-wide visibility.

No behavior change; build and tests are green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/entities/solid.rs

@@ -10,9 +10,9 @@ use glam::Vec3;
 use crate::command::EntityTransform;
 use crate::entities::common::{edit_prop as edit, square_grip};
 use crate::entities::traits::{Grippable, PropertyEditable, Transformable, TruckConvertible};
-use crate::scene::acad_to_truck::{TruckEntity, TruckObject};
-use crate::scene::object::{GripApply, GripDef, PropSection};
-use crate::scene::wire_model::SnapHint;
+use crate::scene::convert::acad_to_truck::{TruckEntity, TruckObject};
+use crate::scene::model::object::{GripApply, GripDef, PropSection};
+use crate::scene::model::wire_model::SnapHint;
 
 fn v3(v: &acadrust::types::Vector3) -> [f64; 3] {
     [v.x, v.y, v.z]
@@ -147,14 +147,14 @@ impl PropertyEditable for Solid {
 
 impl Transformable for Solid {
     fn apply_transform(&mut self, t: &EntityTransform) {
-        crate::scene::transform::apply_standard_entity_transform(self, t, |entity, p1, p2| {
+        crate::scene::view::transform::apply_standard_entity_transform(self, t, |entity, p1, p2| {
             for corner in [
                 &mut entity.first_corner,
                 &mut entity.second_corner,
                 &mut entity.third_corner,
                 &mut entity.fourth_corner,
             ] {
-                crate::scene::transform::reflect_xy_point(&mut corner.x, &mut corner.y, p1, p2);
+                crate::scene::view::transform::reflect_xy_point(&mut corner.x, &mut corner.y, p1, p2);
             }
         });
     }