0.12.0

Changed

• The library grid now renders only the books actually in or near view,
  instead of accumulating every card you've ever scrolled past — memory and
  DOM size stay flat no matter how far you scroll a large library.
• Covers now get a small cached thumbnail (generated in the background,
  same pass that already fills in chapters) that the grid, series view, and
  duplicates finder load instead of the full-size image. Combined with the
  grid change above, scrolling back into a section you'd already passed no
  longer visibly pauses to redecode covers. The book view still shows your
  covers at full resolution.