AnnotationSync v2.0.0 🎉

The biggest release yet — new sync capabilities, a major internal
refactor, a hardened end-to-end test suite, and a new translation.

✨ New Features

• Full Library Sync — scan your entire library for books with
  annotations that were never synced (not just the currently dirty
  ones) and sync them all in one pass.
• Device Purging — remove a stale or retired device's entries from
  reading progress sync, with a one-click undo.

🌍 Localization

• Added Simplified Chinese (zh_CN) translation.
• Refreshed and completed existing translations.

🐛 Fixes

• Fixed a WebDAV sync_server reference bug that could corrupt state
  when handed to the storage provider.
• Bounded retries on persistent sync conflicts to prevent runaway
  loops.
• No-op resyncs no longer trigger a broadcast, keeping sync idempotent.
• Settings exclusion filters are now enforced at the push boundary.

🏗️ Under the Hood

• Major refactor of the sync orchestration: extracted dedicated modules
  for settings sync, the changed-documents queue, UI suppression, and
  provider adaptation — smaller, more testable, more maintainable code.
• A sprawling new real-WebDAV end-to-end test harness covering
  two-device sync, progress sync, merge conflicts, bookmark restore,
  highlight resizing, the pending queue, network reconnects, and more —
  dozens of new scenarios guarding against regressions.
• CI bumped to KOReader v2026.07.2.

📖 Docs

• README now documents Full Library Sync and Device Purging.
• Added a from-scratch guide for setting up a KOReader dev environment.

Full Changelog: v1.9.9999...v2.0.0