feat: Add syntax support for destructuring, labels, and generators

[nyariv]

What changed

This branch expands SandboxJS support for several missing JavaScript language features and brings the runtime behavior closer to native JS.

• added variable destructuring support
• added argument destructuring and default function parameter support
• added labelled statement support
• added generator and async generator support, including resumed next(value) flow, yield expression values, delegation behavior, and constructor shims in the eval context
• updated docs and TODO notes to reflect the new support surface
• added and expanded eval/runtime/security tests for the new syntax and runtime behavior

Why

SandboxJS was still missing a set of common language features that show up in ordinary application code. This branch closes those gaps so more real-world JavaScript can run inside the sandbox without workarounds.

Impact

Users can now evaluate a broader set of JavaScript patterns inside the sandbox, especially around function parameters, destructuring, labels, and generator control flow. The test suite also gets much better coverage around those semantics.

Validation

• npm test -- --runInBand
• npm run lint