Sync fixes:
- Extend stall detection beyond IBD to catch post-IBD sync gaps
- Walk-forward inv continuation to avoid CBlockLocator exponential gap loop
- Track walk-forward progress for stall recovery without restarting from scratch
GUI fixes:
- Load transactions synchronously in constructor (deferred QTimer never fired)
- Use beginResetModel/endResetModel instead of deprecated reset()
- Schedule full refresh on TRY_LOCK failure to avoid dropped CT_NEW notifications
- Only update cachedNumBlocks after successful balance check (prevents permanent loss)
- Add GetAllBalances() single-pass balance retrieval with TRY_LOCK
Bootstrap:
- Add trusted snapshot manifest verification for bootstrap archives
- Add IsKnownCheckpoint() to validate manifest against compiled-in checkpoints
- Skip txleveldb rebuild when verified manifest is present
Bump version to 5.3.7 across all packaging manifests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>