tauri-runtime-servocat 3.1.0

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. v3.1.0 replaces the local `scale_paint_commands` helper with paint-cat 0.2's upstream `PaintCommand::scaled(factor)` / `DisplayList::scaled(factor)` API, so the per-variant scaling logic lives in the crate that owns the display-list type. Zoom semantics are unchanged from v3.0; the rasterizer still re-draws at the larger size for crisp text. The Servo no-AI policy disqualifies upstream contribution; this is the AI-built parallel.