web-api-cat 0.6.3

Bindings between boa-cat (JS engine) and the DOM (html-cat tree) plus fetch (net-cat). v0.6.3 adds `Element.classList` as a `DOMTokenList`-shaped object exposing `add(token)`, `remove(token)`, `contains(token)`, and `toggle(token)`. All writebacks flow through the existing `setAttribute('class', ...)` mirror path so `className`, `getAttribute('class')`, and `__attributes.class` stay in sync. Seventh sub-crate of a Servo-replacement webview runtime targeting Tauri.