feat(f64): command layer compiles on DVec3

Whole command/snap/grip/cursor chain now builds on f64 DVec3 end to end,
so picked points, snaps and grip drags stay precise at UTM-scale
coordinates instead of quantizing to ~0.5 m through f32.

- All ~80 command files migrated: draw (line/circle/arc/ellipse/shapes
  in full f64; others via point methods), modify, annotate, insert, view,
  inquiry, layers, groups, clipboard, layout.
- Entity apply_grip impls updated for GripApply::{Absolute,Translate}(DVec3).
- Construction sites (EntityTransform/CmdResult/DynAnchor) emit DVec3;
  wire-preview boundaries cast to f32 only at the GPU edge.
- Modify/annotate commands keep internal Vec3 geometry where precision is
  non-critical, casting at the DVec3 boundary; key draw commands store f64.

Builds clean (no warnings). Visual verification of crosshair/snap/grip at
extreme UTM zoom pending.

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

src/modules/draw/inquiry/area.rs

@@ -1,7 +1,7 @@
 // AREA command — compute area and perimeter of a polygon picked point by point.
 // Press Enter to close and calculate.
 
-use glam::Vec3;
+use glam::{DVec3, Vec3};
 
 use crate::command::{CadCommand, CmdResult};
 use crate::scene::model::wire_model::WireModel;
@@ -32,7 +32,7 @@ impl CadCommand for AreaCommand {
         }
     }
 
-    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+    fn on_point(&mut self, pt: DVec3) -> CmdResult { let pt = pt.as_vec3();
         self.points.push(pt);
         CmdResult::NeedPoint
     }
@@ -56,7 +56,7 @@ impl CadCommand for AreaCommand {
         CmdResult::Measurement(msg)
     }
 
-    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+    fn on_mouse_move(&mut self, pt: DVec3) -> Option<WireModel> { let pt = pt.as_vec3();
         if self.points.is_empty() {
             return None;
         }

src/modules/draw/inquiry/dist.rs

@@ -1,6 +1,6 @@
 // DIST command — measure distance and angle between two picked points.
 
-use glam::Vec3;
+use glam::{DVec3, Vec3};
 
 use crate::command::{CadCommand, CmdResult};
 use crate::scene::model::wire_model::WireModel;
@@ -28,7 +28,7 @@ impl CadCommand for DistCommand {
         }
     }
 
-    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+    fn on_point(&mut self, pt: DVec3) -> CmdResult { let pt = pt.as_vec3();
         if let Some(p1) = self.first {
             let delta = pt - p1;
             let dist = delta.length();
@@ -56,7 +56,7 @@ impl CadCommand for DistCommand {
         CmdResult::Cancel
     }
 
-    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+    fn on_mouse_move(&mut self, pt: DVec3) -> Option<WireModel> { let pt = pt.as_vec3();
         let p1 = self.first?;
         Some(WireModel {
             name: "dist_preview".into(),

src/modules/draw/inquiry/divide.rs

@@ -6,7 +6,7 @@ use std::f64::consts::PI;
 use acadrust::entities::Point as PointEnt;
 use acadrust::types::Vector3;
 use acadrust::{EntityType, Handle};
-use glam::Vec3;
+use glam::DVec3;
 
 use crate::command::{CadCommand, CmdResult};
 
@@ -43,7 +43,7 @@ impl CadCommand for DivideCommand {
         self.target.is_none()
     }
 
-    fn on_entity_pick(&mut self, handle: Handle, _pt: Vec3) -> CmdResult {
+    fn on_entity_pick(&mut self, handle: Handle, _pt: DVec3) -> CmdResult {
         if handle.is_null() {
             return CmdResult::NeedPoint;
         }
@@ -71,7 +71,7 @@ impl CadCommand for DivideCommand {
         Some(CmdResult::DivideEntity { handle, n })
     }
 
-    fn on_point(&mut self, _pt: Vec3) -> CmdResult {
+    fn on_point(&mut self, _pt: DVec3) -> CmdResult {
         CmdResult::NeedPoint
     }
     fn on_enter(&mut self) -> CmdResult {
@@ -112,7 +112,7 @@ impl CadCommand for MeasureCommand {
         self.target.is_none()
     }
 
-    fn on_entity_pick(&mut self, handle: Handle, _pt: Vec3) -> CmdResult {
+    fn on_entity_pick(&mut self, handle: Handle, _pt: DVec3) -> CmdResult {
         if handle.is_null() {
             return CmdResult::NeedPoint;
         }
@@ -148,7 +148,7 @@ impl CadCommand for MeasureCommand {
         })
     }
 
-    fn on_point(&mut self, _pt: Vec3) -> CmdResult {
+    fn on_point(&mut self, _pt: DVec3) -> CmdResult {
         CmdResult::NeedPoint
     }
     fn on_enter(&mut self) -> CmdResult {

src/modules/draw/inquiry/id.rs

@@ -1,6 +1,6 @@
 // ID command — report coordinates of a picked point.
 
-use glam::Vec3;
+use glam::DVec3;
 
 use crate::command::{CadCommand, CmdResult};
 
@@ -21,7 +21,7 @@ impl CadCommand for IdCommand {
         "ID  Specify point:".into()
     }
 
-    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+    fn on_point(&mut self, pt: DVec3) -> CmdResult {
         // Drawing plane is world XY (z = elevation).
         let x = pt.x;
         let y = pt.y;