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/modules/draw/defaults.rs

@@ -4,29 +4,29 @@
 use std::cell::Cell;
 
 thread_local! {
-    static CIRCLE_RADIUS:   Cell<f32> = Cell::new(1.0);
-    static CIRCLE_DIAM:     Cell<f32> = Cell::new(2.0);
-    static ROTATE_ANGLE:    Cell<f32> = Cell::new(0.0);   // degrees
-    static SCALE_FACTOR:    Cell<f32> = Cell::new(1.0);
-    static OFFSET_DIST:     Cell<f32> = Cell::new(1.0);
-    static FILLET_RADIUS:   Cell<f32> = Cell::new(1.0);
-    static CHAMFER_DIST1:   Cell<f32> = Cell::new(10.0);
-    static CHAMFER_DIST2:   Cell<f32> = Cell::new(10.0);
-    static ARRAY_ROWS:      Cell<f32> = Cell::new(2.0);
-    static ARRAY_COLS:      Cell<f32> = Cell::new(2.0);
-    static ARRAY_ROW_SP:    Cell<f32> = Cell::new(100.0);
-    static ARRAY_COL_SP:    Cell<f32> = Cell::new(100.0);
-    static ARRAY_P_COUNT:   Cell<f32> = Cell::new(6.0);
-    static ARRAY_P_ANGLE:   Cell<f32> = Cell::new(360.0); // degrees
-    static ARRAY_PATH_COUNT: Cell<f32> = Cell::new(6.0);
+    static CIRCLE_RADIUS:   Cell<f64> = Cell::new(1.0);
+    static CIRCLE_DIAM:     Cell<f64> = Cell::new(2.0);
+    static ROTATE_ANGLE:    Cell<f64> = Cell::new(0.0);   // degrees
+    static SCALE_FACTOR:    Cell<f64> = Cell::new(1.0);
+    static OFFSET_DIST:     Cell<f64> = Cell::new(1.0);
+    static FILLET_RADIUS:   Cell<f64> = Cell::new(1.0);
+    static CHAMFER_DIST1:   Cell<f64> = Cell::new(10.0);
+    static CHAMFER_DIST2:   Cell<f64> = Cell::new(10.0);
+    static ARRAY_ROWS:      Cell<f64> = Cell::new(2.0);
+    static ARRAY_COLS:      Cell<f64> = Cell::new(2.0);
+    static ARRAY_ROW_SP:    Cell<f64> = Cell::new(100.0);
+    static ARRAY_COL_SP:    Cell<f64> = Cell::new(100.0);
+    static ARRAY_P_COUNT:   Cell<f64> = Cell::new(6.0);
+    static ARRAY_P_ANGLE:   Cell<f64> = Cell::new(360.0); // degrees
+    static ARRAY_PATH_COUNT: Cell<f64> = Cell::new(6.0);
 }
 
 macro_rules! accessors {
     ($get:ident, $set:ident, $var:ident) => {
-        pub fn $get() -> f32 {
+        pub fn $get() -> f64 {
             $var.with(|c| c.get())
         }
-        pub fn $set(v: f32) {
+        pub fn $set(v: f64) {
             $var.with(|c| c.set(v));
         }
     };