ECMAScript runtime: native built-ins (console, Math, JSON, parseInt, isNaN, Promise, ...) that the boa-cat engine exposes to scripts. v0.3.2 adds `JSON.parse(source)` alongside the existing `JSON.stringify`: a hand-rolled recursive-descent JSON parser that handles null / booleans / numbers (including scientific notation) / strings (with `\"` / `\\` / control-character / `\uXXXX` escapes) / arrays / objects and rebuilds them as boa-cat `Value`s on the heap. Throws `SyntaxError` on malformed input; the heap is snapshotted and restored on the error path so partial allocations don't leak.