v0.1.9 - pin sidebar grid track against WebKit min-content inflation

Fixed

• iPad Safari sidebar-track inflation:
  grid-template-columns: minmax(0, var(--col-aside)) 1fr forces the
  sidebar track's minimum to zero so no descendant can widen it, and
  min-width: 0 on .sidebar / .sidebar-bot breaks the flex chain
  so monospace min-content from TOC <pre> content cannot bubble up
  to the grid.