ecma-runtime-cat 0.3.1

ECMAScript runtime: native built-ins (console, Math, JSON, parseInt, isNaN, Promise, ...) that the boa-cat engine exposes to scripts. v0.3.1 bumps to boa-cat 0.7 + ecma-parse-cat 0.3 so the shared parser / AST version tracks across the workspace; no source change since this crate doesn't itself parse user scripts and the v0.3 Promise built-in already targets the boa-cat 0.6-style promise API.