Edit Sketch no longer shows bodies a later feature deletes (#1329)

Fixes #1167. While a sketch is edited, a body that a rolled-off, unsuppressed Remove deletes is not shown (unless the sketch is built on it); the history stays rolled back, only the view changes. Drawing, picking, screenshots, thumbnails and the browser's Bodies folder agree; document.inspect reports removed_later. Checked on main + this branch: cargo check --workspace, the engine sketch_edit_removed/occurrences tests and the UI viewport/browser tests.

crates/engine/src/lib.rs

@@ -219,6 +219,7 @@ pub struct Session {
     pub pending_moves: std::collections::BTreeMap<u64, solidcraft_doc::Mat>,
     world_cache: std::sync::Mutex<Option<WorldCache>>,
     occurrence_visibility_cache: std::sync::Mutex<Option<occurrences::VisibilityCache>>,
+    removed_later_cache: std::sync::Mutex<Option<occurrences::RemovedLaterCache>>,
     /// Features copied with `timeline.copy` (pasted by `timeline.paste`).
     pub clipboard: Vec<solidcraft_doc::Feature>,
     /// Section Analysis: a view cut by a plane (origin, unit normal; the normal side is hidden).
@@ -323,6 +324,7 @@ impl Session {
             pending_moves: Default::default(),
             world_cache: Default::default(),
             occurrence_visibility_cache: Default::default(),
+            removed_later_cache: Default::default(),
             clipboard: Vec::new(),
             section: None,
             analysis: None,
@@ -788,6 +790,7 @@ impl Session {
             pending_moves: self.pending_moves.clone(),
             world_cache: std::sync::Mutex::new(self.world_cache.lock().ok().and_then(|cache| cache.clone())),
             occurrence_visibility_cache: Default::default(),
+            removed_later_cache: Default::default(),
             clipboard: self.clipboard.clone(),
             section: None,
             analysis: None,
@@ -946,6 +949,8 @@ mod profile_curves_tests;
 #[cfg(test)]
 mod profile_refs_tests;
 #[cfg(test)]
+mod sketch_edit_removed_tests;
+#[cfg(test)]
 mod split_face_tests;
 #[cfg(test)]
 mod tests;