Bug fixes for device sync, portfolio returns, and startup.
- Faster, smaller encrypted device transfers, with broker holdings included and clearer pairing progress.
- Consistent holdings-account returns after full and partial recalculations.
- Fixed the Linux startup crash caused by native credential storage (#1819).
- Clearer self-hosted profile startup errors and recovery from interrupted sessions.
Update both devices to 3.9.1 before pairing. If older return history is incorrect, run a full portfolio rebuild.
