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 <[email protected]>

src/modules/insert/solid3d_cmds.rs

@@ -61,7 +61,7 @@ impl CadCommand for ExtrudeCommand {
         self.step = ExtrudeStep::Height;
         CmdResult::NeedPoint
     }
-    fn on_point(&mut self, pt: DVec3) -> CmdResult { let pt = pt.as_vec3();
+    fn on_point(&mut self, pt: DVec3) -> CmdResult {
         if self.step == ExtrudeStep::Height {
             return CmdResult::ExtrudeEntity {
                 handle: self.target_handle,
@@ -76,7 +76,7 @@ impl CadCommand for ExtrudeCommand {
     }
     fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
         text.trim()
-            .parse::<f32>()
+            .parse::<f64>()
             .ok()
             .filter(|&h| h.abs() > 1e-6)
             .map(|h| CmdResult::ExtrudeEntity {