## Summary
It would be nice to switch back to the file list from an Reader activity
via a short back button press. This change adds an Reader option to
switch the default behavior, so a short back button press in the Reader
activity can now go back to the file list, and a long press on back goes
back to the home view. This does a fair bit of refactoring, introducing
a new constant for the ms limit.
* **What changes are included?**
- Changes to the translation
- Additional global Reader option
- Refactoring of the back button behavior in the Reader activity
Implements createUser() endpoint to allow account creation via the
KOSync protocol. Changes default sync server from sync.koreader.rocks to
sync.crosspointreader.com with migration logic to preserve existing
users' server settings. Extends sync protocol to include position data
(spine index, page numbers, xpath) that crosspoint-sync supports while
remaining compatible with standard kosync servers.
## Summary
Make KOReader progress sync a one-click flow for common cases while
keeping the existing manual mode available.
### Changes
- Add a **Sync Behavior** setting:
- **Smart sync** for new configurations
- **Ask every time** for manual control
- Preserve **Ask every time** when migrating an existing credential file
that predates this setting.
- In Smart mode:
- upload local progress when no remote record exists;
- show a short confirmation when already synced;
- upload when local progress is further ahead;
- apply remote progress when remote progress is further ahead.
- Probe both KOReader document-matching hashes before making the Smart
decision, while keeping uploads on the user's configured matching
method.
- Auto-return after successful Smart terminal states, with Back/Confirm
still available.
- Persist the setting alongside the current credential, matching-method,
and send-metadata fields.
- Document both behaviors in the user guide.
## Additional context
This pairs well with #2189 (smart Wi-Fi auto-connect), but does not
depend on it. It does not add background Wi-Fi or passive network
detection; sync is still triggered by the user from the reader menu.
Smart sync uses the furthest progress because CrossPoint does not
currently persist local progress timestamps. Users who prefer explicit
conflict resolution can select **Ask every time**.
## Verification
- `git diff --check`
- `platformio check --fail-on-defect low --fail-on-defect medium
--fail-on-defect high` — no defects
- `platformio run -e default` — firmware build successful
- The original implementation was manually smoke-tested on an X4 device.
---
### AI Usage
Did you use AI tools to help write this code? _**YES**_
AI tools were used to inspect the codebase, draft and review the
implementation, resolve the rebase against current `develop`, and
prepare the PR text. The resulting firmware was built locally.
---------
Co-authored-by: Alexander Hoffer <git@alexanderhoffer.com>
Co-authored-by: Alexander Hoffer <contact@alexanderhoffer.com>
