feat: new split-screen #171

playground/dialog/index.html

playground/dialog/main.js

playground/dialog/main.pcss

playground/issues/142.html

playground/issues/144.html

playground/issues/152.html

playground/issues/154.html

playground/issues/158.html

playground/split-screen/index.html

playground/split-screen/main.js

playground/split-screen/main.pcss

playground/tab/index.html

playground/tab/main.mjs

playground/vite.config.js

source/components/form/tabs.mjs

source/components/host/overlay.mjs

source/components/host/viewer.mjs

source/components/layout/namespace.mjs

source/components/layout/split-screen.mjs

source/components/layout/style/split-screen.pcss