tauri-runtime-servocat 3.26.0

Servo-replacement runtime for Tauri: wires html-cat, css-cat, dom-cat, layout-cat, paint-cat, net-cat, boa-cat, ecma-runtime-cat, and web-api-cat into a single rendering + scripting pipeline. v3.26.0 picks up web-api-cat 0.7.12 + 0.7.13: user-supplied webview scripts get sibling combinators (`a + b` adjacent, `a ~ b` general), `Element.matches(selector)` predicate, `Element.closest(selector)` (walks ancestors inclusive of self), and structural pseudo-classes (`:first-child`, `:last-child`, `:only-child`). No tauri-runtime-servocat source change beyond the manifest. Seventh sub-crate of a Servo-replacement webview runtime targeting Tauri.