2.8.0

Added

• An embedded page announces busy: true when Submit starts a run, uploads
  included, and false when it ends, whatever the outcome. A failed upload or
  a broken response announce no error, but they still close the bracket; a
  form the browser rejects never opens one. listen() and openModal() take
  onBusy(busy), so a host can tuck a slow modal away and keep working.
  Hosts that do not know the kind ignore it, as the protocol already said.

Changed

• The README shows the divide form again under its example, by its address on
  the documentation site so it also renders on PyPI. docs/overview.md drops
  its copy, since the site's Overview page starts with the README.

Fixed

• A Pillow image in mode I (32-bit integers) is returned again with Pillow
  13, which no longer saves that mode as PNG: it is sent as 16-bit grayscale
  (I;16), values above 65535 clipped. I;16 images are now sent as they
  are instead of being converted to RGB.
• The test suite runs again with pytest-asyncio 1.4, which warns while
  asyncio_default_fixture_loop_scope is unset; it is set to "function".