v0.1.8 - pin sidebar track, frame inline code with ticks, link modeline SHA

Changed

• Inline <code> loses the border-bottom that read as a link and
  gains content prefix / suffix in --ink-3.
• Modeline optionally links the build SHA to a GitHub tree URL via
  Site.Params.repoURL; falls back to a plain span when unset.

Fixed

• min-width: 0 on .sidebar-col to stop WebKit from expanding the
  fixed grid track when a TOC widget's non-wrapping content reports
  a larger min-content.