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>

xtask/src/main.rs

@@ -25,6 +25,9 @@ commands:
   test [CARGO ARGS] [-- TEST ARGS]
                   build the tests with the ci profile, then run every test binary at once
                   (and the doc tests alongside)
+  corpus [--part NAME] [--no-write]
+                  build every meshing test corpus part (tests/corpus, analytic shapes), tessellate
+                  and mesh it, and write the results to docs/meshing/corpus.md (release build)
   wasm            cargo check every library crate for wasm32-unknown-unknown
   ci              fmt --check, assets, licences --check, layers, clippy -D warnings, then the tests
                   with the wasm check alongside (stops at the first failing step)
@@ -42,6 +45,12 @@ fn main() -> ExitCode {
             test::run(cargo_args, test_args, vec![test::doc_tests(cargo_args, test_args)])
         }
         Some("ci") => cmd_ci(),
+        Some("corpus") => {
+            // A binary of the testkit, so xtask itself stays free of SolidCraft.
+            let mut c = cargo();
+            c.args(["run", "--release", "-p", "modelcraft-testkit", "--bin", "corpus", "--"]).args(&rest);
+            run(c, "corpus")
+        }
         Some("wasm") => cmd_wasm(),
         Some("-h" | "--help" | "help") | None => {
             print!("{USAGE}");