mini_racer-csim 0.21.1.0

A private fork of mini_racer (minimal embedded V8 for Ruby) adding browser-level behavior used by capybara-simulated: the V8 ES Module API, cross-process bytecode caching, an opt-in host namespace, realm reset, and a batched module-graph loader with a URL module registry. These are niche browser-fidelity features; general users should use upstream mini_racer. The library is still required as `mini_racer` and exposes the `MiniRacer` module, so it stays a drop-in for code targeting mini_racer.