- Opening from the copy starts on the page the copy could show, not the
  first page (initializeForStrategy).
- Without a copy (web, share links) every read path is main's again: a
  page read refuses at once while disconnected, and selecting a page
  always asks the server.
- A reconnect while a walk or read is running walks again after it,
  however it ends.
- A strategy counts as refreshed only once all its images are on disk, so
  a failed download is retried by the next walk.
- A test runs every element kind through hydration and the copied-page
  check and expects them to agree.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>