This updates Rollup and replaces Buble with Babel (we're already using Babel anyway) to add babel-preset-solid for compiling Solid JSX expressions.

At the moment this breaks the current SSR feature.

We had to pin the `colors` library (used by live-server)because the
author wilfully broke it to disrupt millions of users.
Marak/colors.js#285

…with props, then use them as JSX

Playwright had some in-range breaking changes (regressions): microsoft/playwright#10819 and microsoft/playwright#11570

Playwright tests need to `await onceRendered()` after each route navigation to wait for render to finish before testing the state of the rendered DOM. Tests were flaky because they were looking for DOM before render finished (sometimes).

Additionally, this fixes one test that was failing only locally, but not in CI, due to a RegExp check against page.url() (not sure why it would differ on CI vs local, but now the URL is explicit).