Nextup 1.5.5

Nothing here changes how you use Nextup, and your data is untouched.

• Two libraries updated: Werkzeug to 3.1.9 and cryptography to 50.0.2.
• The image is built from one exact base image, so the same version always
  builds the same image. Every release is now scanned for known security holes
  before it is published, and a serious one stops the release.
• The published source has its comments stripped to keep it lean.
• The website works on phones again. The email section ran off the side of
  the screen, and the menu wrapped onto two rows at some widths. Links are
  easier to tap and the small print is larger.