Starts a watch session: one browser, one page, every test file in a single bundle, behind an HTTP server that stays up. Resolves once the initial run has finished and the watchers are armed — the returned WatchSession is how the caller stops it again.

import type { watch } from './test.ts';
import type { Config } from '../types.ts';
// Defined, not invoked: launches Chrome and leaves it watching.
async function watchSuite(startWatching: typeof watch, config: Config) {
  const session = await startWatching(config);
  return session.url; // 'http://localhost:1234'
}