feat(kernel): modifiers report exact face and edge history

Fillets (local, loop, rolling ball, corner, variable, chord), chamfers
(cutters, local corners, loops, two sides), shell, draft, offset faces,
split face/body, delete face, patch/copy/stitch/trim/extend and
transforms record their history over [body] while they build: faces
rebuilt from the body's, blends in place of edges (corner patches in
place of the edges at the corner), shell walls as offsets, edges as
pieces of the body's or where two faces meet. Multi-step operations
compose each step. The push-face offset fallback now has history, and
the bore union composes its narrowed tool.

A reflection reorders a body's edges, so transforms now match edges by
identity (mirrored copies reported the wrong edges).

Refs #136

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J53sR6gEaVt56soFDpTck8

crates/kernel/src/heal.rs

@@ -407,12 +407,7 @@ fn planar_surfaces(shell: &mt::Shell, tol: f64) -> Option<mt::Shell> {
 /// Heal a solid; returns the input unchanged when nothing applies or healing fails.
 #[cfg(test)]
 pub fn heal(solid: Solid, size: f64) -> Solid {
-    heal_keep(solid, size, &[])
-}
-
-/// [`heal`], keeping faces apart along lines they were split along on purpose.
-pub(crate) fn heal_keep(solid: Solid, size: f64, keep: &[Vec<Vec3>]) -> Solid {
-    healed(solid, size, keep, false).0
+    healed(solid, size, &[], false).0
 }
 
 /// What healing made each face and edge of its result from.
@@ -467,8 +462,9 @@ impl HealMap {
     }
 }
 
-/// [`heal_keep`], with what each face and edge of the result was made from (`None` when that
-/// could not be followed).
+/// Heal a solid (the input unchanged when nothing applies or healing fails), keeping faces apart
+/// along lines they were split along on purpose (`keep`), with what each face and edge of the
+/// result was made from (`None` when that could not be followed).
 pub(crate) fn heal_traced(solid: Solid, size: f64, keep: &[Vec<Vec3>]) -> (Solid, Option<HealMap>) {
     healed(solid, size, keep, true)
 }