Meshing test corpus built with SolidCraft; assembly placement in open_design (#11)

* geometry: build designs from SolidCraft command scripts (feature scripts)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* geometry: place component bodies through their occurrences when opening a design

An assembly's instances were missing and moved components sat at their own origin.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Meshing test corpus: 16 SolidCraft recipes, analytic shapes, loader and runner

modelcraft-testkit holds the corpus (tests/corpus/<name>/recipe.json run through SolidCraft's
engine, then opened as a design) and the runner binary behind cargo xtask corpus.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* docs: corpus results, test corpus architecture and the scripts feature; licences

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* corpus: measure each body once, check stage widths, simpler loader and runner

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

---------

Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/geometry/src/design.rs

@@ -18,7 +18,8 @@ pub const MAX_DESIGN_BYTES: usize = solidcraft_io::MAX_DESIGN_BYTES;
 #[derive(Debug, Clone)]
 pub struct Design {
     pub name: String,
-    /// The bodies at the end of the timeline, in the design's order.
+    /// The bodies at the end of the timeline, in the design's order, placed in the world: bodies of
+    /// components moved by their occurrences, one body per placement.
     pub bodies: Vec<Shape>,
     /// Features that failed to rebuild. The design still opens with the bodies the rest made,
     /// as it does in SolidCraft.
@@ -63,7 +64,9 @@ pub(crate) fn rebuild(doc: &Document) -> Result<Design> {
         .filter(|r| !r.skipped)
         .filter_map(|r| r.error.as_ref().map(|e| FeatureError { feature: r.name.clone(), message: e.clone() }))
         .collect();
-    let state = model.state();
+    // Placed in the world: a component's bodies through every occurrence of it (an instance is a
+    // body of its own, named after its occurrence path), as SolidCraft displays and exports them.
+    let state = guard("place components", || Ok(solidcraft_doc::world_state(doc, &model.state())))?;
     let mut bodies = Vec::with_capacity(state.bodies.len());
     for b in &state.bodies {
         let faces = guard("name faces", || {