Features:
- restore diagnose command for backup file analysis
- Deep COPY block verification for truncated dump detection
- PGDMP signature and gzip integrity validation
- Detailed error reports with --save-debug-log flag
- Ring buffer stderr capture (prevents OOM on 2M+ errors)
- Error classification with actionable recommendations
TUI Enhancements:
- Automatic dump validity safety check before restore
- Press 'd' in archive browser to diagnose backups
- Press 'd' in restore preview for debug log toggle
- Debug logs saved to /tmp on failure when enabled
Documentation:
- Updated README with diagnose command and examples
- Updated CHANGELOG with full feature list
- Updated restore preview screenshots
