Backend:
- New /api/v1/backup/export endpoint - exports all data as single JSON
- New /api/v1/backup/import endpoint - imports JSON with merge or replace
- Handles vendors, filaments, spools, adjustments, settings
- Remaps IDs to maintain relationships during import
Frontend:
- Added Backup & Restore section to Settings page
- Download Backup button for export
- Import with merge or replace options
- Warning confirmation for replace mode
This enables migrating between PostgreSQL and SQLite databases.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
