refactor(precision): widen command transform scalars and defaults to f64 (#311)

Completes the f64 migration on the CPU data path: the only f32 left now
is the GPU/render/screen layer, which is architecturally required (wgpu
vertex buffers and iced are f32; f64 vertices would double memory).

- EntityTransform::Rotate.angle_rad and Scale.factor are now f64 (the
  transform was already applied in f64 around the DVec3 center, so this
  only preserves the typed angle/factor). apply_standard_transform and
  apply_standard_scale take f64.
- CmdResult::ExtrudeEntity.height and AlignSelected.{angle_rad,scale}
  are f64; the EXTRUDE height parses as f64.
- defaults.rs (last-used construction values: circle radius/diameter,
  rotate angle, scale factor, offset/fillet/chamfer distance, array
  spacing/counts/angle) moved from Cell<f32> to Cell<f64>. Array counts
  round-trip through u32 (exact below 2^53).
- Consumers in circle/array/fillet/offset/rotate/scale/align/solid3d and
  dimension.rs rotate_point/scale_point follow. `as f32` is kept only
  where a value feeds a WireModel rubber-band/ghost (the preview path is
  screen-space f32).

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

src/entities/dimension.rs

@@ -559,16 +559,16 @@ where
     }
 }
 
-fn rotate_point(p: &mut acadrust::types::Vector3, center: DVec3, angle_rad: f32) {
+fn rotate_point(p: &mut acadrust::types::Vector3, center: DVec3, angle_rad: f64) {
     let dx = p.x - center.x;
     let dy = p.y - center.y;
-    let (s, c) = (angle_rad as f64).sin_cos();
+    let (s, c) = angle_rad.sin_cos();
     p.x = center.x + dx * c - dy * s;
     p.y = center.y + dx * s + dy * c;
 }
 
-fn scale_point(p: &mut acadrust::types::Vector3, center: DVec3, factor: f32) {
-    let f = factor as f64;
+fn scale_point(p: &mut acadrust::types::Vector3, center: DVec3, factor: f64) {
+    let f = factor;
     p.x = center.x + (p.x - center.x) * f;
     p.y = center.y + (p.y - center.y) * f;
     p.z = center.z + (p.z - center.z) * f;