Cross-realm shape dictionary mode

Date: 2026-06-13 Area: bytecode

Shape-lite property maps now record their owner realm and switch to dictionary mode when EnsureShape runs from any other realm. This keeps $262.createRealm cross-realm property reads from interning one engine's object layout into another realm-owned shape table while preserving the single-realm cache-hit path as a raw shape-field read. #751. bytecode-vm.md § Inline Caches.