tt-bio-demo v0.5.0

• Pinned tt-bio moves to 0.7.0. Every fold time on every card, the site and
  this handout is re-measured on that release; the numbers barely move, and
  the 0.6.7 Protenix-v2 accuracy fixes are not visible on these targets
  because all seven fold without an MSA.
• The weight-artifact API the weights postinst and the runner both call
  moved into tt_bio.weights upstream; both are ported, and the packaging
  contract test now checks the artifact key as well as the function.
• A finished structure now holds the screen for as long as the NEXT fold can
  afford rather than a flat two seconds, capped per target by its measured
  time to first coordinates: about seven seconds ahead of the long targets,
  unchanged ahead of the short ones, whose whole collapse a flat hold would
  have suppressed.
• The cartoon draws nucleic acids instead of dropping them. A protein/DNA
  complex used to render the protein and silently omit the DNA, and a pure
  DNA or tRNA fold fell back to the old tube renderer by way of an
  exception. Same picture as before for those two, now drawn on purpose.
• A booth with more than one chip comes up showing all of them. --quad still
  forces the grid on a single-chip booth and the new --solo forces one large
  protein; Q toggles either way at runtime, as before.