Bookdrop 2.0.0

PDF conversion now runs on anyform, a Rust engine that renders through
a bundled, self-contained headless Chromium build (via the DevTools
Protocol) instead of the previous Swift-native WKWebView pipeline —
the same class of approach calibre's PDF output uses. TXT/HTML/DOCX
conversion remain Swift-native for now.

What's new

• Full PDFOptions support on the new engine — page size/margins/
  orientation, typography, headers/footers/page numbers, cover and
  table-of-contents toggles all reach the renderer
• Default PDF typography now matches calibre's own defaults (1in margins,
  15pt base font) for a comparable page count/density out of the box
• Async, cancellable conversion with live progress through the Rust/FFI
  boundary

Install: download Bookdrop-2.0.dmg below, drag Bookdrop into
Applications, then right-click → Open on first launch (unsigned build —
see the README for why). Apple Silicon only in this build.