Open large designs faster: meshes, face names and Measure on all cores (#916)

Display meshes after opening, the face names read when a feature finds a face by name, and inspect.measure over all bodies are now worked out per body on plain scoped threads (solidcraft_kernel::for_each_on_threads / map_on_threads), in body order and with the same results; the browser build stays serial.

crates/kernel/src/lib.rs

@@ -56,6 +56,7 @@ mod numbered;
 mod offset;
 mod ops;
 mod par;
+pub use par::{for_each_on_threads, map_on_threads};
 #[cfg(test)]
 mod pinch_tests;
 mod plane_fit;