Walk document.styleSheets so chromatic custom properties on :root/html/body/:host (including @media-nested rules) are hue-shifted via inline setProperty, not just the values returned by getComputedStyle.
Fixes#1393
References: PR #1643 (open, in review) binds the Tweaks toolbar toggle to artifact `.tw-panel` panels via a new `injectTweaksBridge` in `srcdoc.ts` — adjacent surface but different problem. Our fix extends `injectPaletteBridge` to also shift `:root` CSS custom-property colors, which #1643 does not touch.