The Emscripten wrapper exported only the eval family, leaving JS consumers
with no way to snapshot or restore the singleton ChaiScript engine. The
playground in chaiscript.github.io needs that to reset between runs without
reloading the WASM module. Added handle-based wrappers that hide
ChaiScript::State behind an int registry so JS callers don't have to manage
embind object lifetimes, exported them as saveState/restoreState/releaseState,
and added a native regression test that exercises capture, restore, and
release through the same wrapper functions the WASM binding uses.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
