Add three-axis milling with independent CAM and Fusion validation (#1682)

Thanks @CypherNaught-0x.

crates/engine/src/lib.rs

@@ -14,6 +14,8 @@ pub mod crash;
 pub mod frames;
 pub mod fuzz;
 pub mod licences;
+pub mod manufacturing;
+pub use solidcraft_cam as cam;
 pub mod occurrences;
 pub mod params;
 pub mod product_scene;
@@ -252,6 +254,8 @@ pub struct Session {
     /// Host-owned viewport metadata, never saved or included in history.
     render_viewport: Option<Arc<render::ExecutorDescriptor>>,
     render_jobs: render_jobs::Jobs,
+    /// Derived, immutable CAM jobs; not persisted or copied into undo snapshots.
+    pub cam_jobs: manufacturing::Jobs,
     /// The visibility the design file holds (what `is_dirty` compares with).
     saved_visibility: Visibility,
     /// States to go back to (`edit.checkpoint`, `edit.restore_checkpoint`): how batches of
@@ -377,6 +381,7 @@ impl Session {
             camera: None,
             render_viewport: None,
             render_jobs: Default::default(),
+            cam_jobs: Default::default(),
             #[cfg(test)]
             evaluations: 0,
             crash_journal: false,
@@ -844,6 +849,7 @@ impl Session {
             camera: self.camera,
             render_viewport: self.render_viewport.clone(),
             render_jobs: self.render_jobs.scratch(),
+            cam_jobs: Default::default(),
             saved_visibility: self.saved_visibility.clone(),
             #[cfg(test)]
             evaluations: 0,