v0.4.1

Changed

• Python & JS now require kymostudio-core ^0.4 (>=0.4,<0.5 / ^0.4),
  up from ^0.3. This activates the kymo … out.pdf SVG → vector PDF path in
  the Python and JS CLIs (it calls the core's svg_to_pdf, new in 0.4.0). The
  floor raise lands one release after 0.4.0 so the floor always points at an
  already-published core (docs/RELEASING.md); 0.4.0 published the core, so CI
  and installs now resolve it cleanly. No API changes.