wip(f64): convert command layer to DVec3 (in progress)

Migrate the command/snap/grip/cursor chain from f32 Vec3 to f64 DVec3 so
picked points, snaps and grip drags stay precise at UTM-scale coordinates
(f32 quantizes to ~0.5 m there).

Done so far:
- command/mod.rs: EntityTransform, CmdResult points, CadCommand point
  methods, TangentObject already DVec3 (radius f64).
- snap: SnapResult.world DVec3; world_to_screen/try_pt DVec3.
- GripApply -> DVec3; grip find/state (GripEdit) f64; camera
  pick_on_plane_f64 / pick_on_target_plane_f64; scene paper_to_model_f64.
- update.rs click + mouse-move + grip-drag pipelines route precise DVec3
  to on_point/on_preview_wires/on_entity_pick; ortho/polar cast at the
  UcsXform boundary only.
- cmd_result dispatch, transform helpers, dimension/arc/circle/multileader
  apply_grip, circle/arc/ellipse/shapes draw commands, array modify.

Tree does NOT compile yet (~236 errors remain across modify/annotate/
insert command files + entity apply_grip impls); committed at user request
to checkpoint progress.

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

src/scene/view/camera.rs

@@ -233,9 +233,24 @@ impl Camera {
     }
 
     pub fn pick_on_target_plane(&self, screen: Point, bounds: Rectangle) -> Vec3 {
+        self.pick_on_target_plane_f64(screen, bounds).as_vec3()
+    }
+
+    /// f64 variant of [`pick_on_plane`] — keeps the cursor precise at UTM-scale.
+    pub fn pick_on_plane_f64(
+        &self,
+        screen: Point,
+        bounds: Rectangle,
+        plane_normal: Vec3,
+        plane_point: glam::DVec3,
+    ) -> glam::DVec3 {
+        self.unproject_on_plane_f64(screen, bounds, plane_normal, plane_point)
+    }
+
+    /// f64 variant of [`pick_on_target_plane`].
+    pub fn pick_on_target_plane_f64(&self, screen: Point, bounds: Rectangle) -> glam::DVec3 {
         let forward = (self.target.as_vec3() - self.eye()).normalize_or(Vec3::NEG_Z);
         self.unproject_on_plane_f64(screen, bounds, forward, self.target)
-            .as_vec3()
     }
 
 

src/scene/view/transform.rs

@@ -1,14 +1,14 @@
 use acadrust::types::{Transform, Vector3};
-use glam::Vec3;
+use glam::DVec3;
 
 use crate::command::EntityTransform;
 
 #[inline]
-fn to_v3(v: Vec3) -> Vector3 {
-    Vector3::new(v.x as f64, v.y as f64, v.z as f64)
+fn to_v3(v: DVec3) -> Vector3 {
+    Vector3::new(v.x, v.y, v.z)
 }
 
-pub fn apply_standard_transform<T>(entity: &mut T, center: Vec3, angle_rad: f32)
+pub fn apply_standard_transform<T>(entity: &mut T, center: DVec3, angle_rad: f32)
 where
     T: acadrust::Entity,
 {
@@ -19,7 +19,7 @@ where
     entity.apply_transform(&t);
 }
 
-pub fn apply_standard_scale<T>(entity: &mut T, center: Vec3, factor: f32)
+pub fn apply_standard_scale<T>(entity: &mut T, center: DVec3, factor: f32)
 where
     T: acadrust::Entity,
 {
@@ -31,7 +31,7 @@ where
 pub fn apply_standard_entity_transform<T, F>(entity: &mut T, t: &EntityTransform, mirror: F)
 where
     T: acadrust::Entity,
-    F: FnOnce(&mut T, Vec3, Vec3),
+    F: FnOnce(&mut T, DVec3, DVec3),
 {
     match t {
         EntityTransform::Translate(d) => entity.translate(to_v3(*d)),
@@ -47,7 +47,7 @@ where
 /// `Transform`, for delegating MIRROR to acadrust's entity-aware
 /// `apply_transform` paths (which handle direction flags, stored-angle
 /// conventions and bulges themselves). Degenerate line → identity.
-pub fn reflection_about_xy_line(p1: Vec3, p2: Vec3) -> acadrust::types::Transform {
+pub fn reflection_about_xy_line(p1: DVec3, p2: DVec3) -> acadrust::types::Transform {
     use acadrust::types::{Matrix4, Transform};
     let dx = (p2.x - p1.x) as f64;
     let dy = (p2.y - p1.y) as f64;
@@ -63,7 +63,7 @@ pub fn reflection_about_xy_line(p1: Vec3, p2: Vec3) -> acadrust::types::Transfor
     Transform::from_matrix(m)
 }
 
-pub fn reflect_xy_point(x: &mut f64, y: &mut f64, p1: Vec3, p2: Vec3) {
+pub fn reflect_xy_point(x: &mut f64, y: &mut f64, p1: DVec3, p2: DVec3) {
     let ax = (p2.x - p1.x) as f64;
     let ay = (p2.y - p1.y) as f64;
     let len2 = ax * ax + ay * ay;
@@ -79,7 +79,7 @@ pub fn reflect_xy_point(x: &mut f64, y: &mut f64, p1: Vec3, p2: Vec3) {
     *y = p1.y as f64 + my;
 }
 
-pub fn mirror_xy_line(line: &mut acadrust::entities::Line, p1: Vec3, p2: Vec3) {
+pub fn mirror_xy_line(line: &mut acadrust::entities::Line, p1: DVec3, p2: DVec3) {
     reflect_xy_point(&mut line.start.x, &mut line.start.y, p1, p2);
     reflect_xy_point(&mut line.end.x, &mut line.end.y, p1, p2);
 }
@@ -171,8 +171,8 @@ mod mirror_delegation_tests {
 
         // Mirror across the vertical line x = 5.
         h.apply_transform(&EntityTransform::Mirror {
-            p1: Vec3::new(5.0, 0.0, 0.0),
-            p2: Vec3::new(5.0, 1.0, 0.0),
+            p1: DVec3::new(5.0, 0.0, 0.0),
+            p2: DVec3::new(5.0, 1.0, 0.0),
         });
 
         let edges = &h.paths[0].edges;