web-api-cat 0.6.8

Bindings between boa-cat (JS engine) and the DOM (html-cat tree) plus fetch (net-cat). v0.6.8 lands parent-backref infrastructure: every element gets a hidden `__parent__` slot (Object when attached, Null when detached or root), every structural mutator (`appendChild` / `removeChild` / `insertBefore` / `replaceChild` / `innerHTML` setter / `cloneNode` deep-children) routes through shared `set_parent_backref` / `clear_parent_backref` helpers, and `parentElement` / `parentNode` accessor-getters plus `Element.remove()` ride on top. Seventh sub-crate of a Servo-replacement webview runtime targeting Tauri.