Replace JSON-based backup system with SQLite export/import functionality:
**Export Features:**
- Generate SQLite database files with complete user data
- Export all tables: SSH hosts, credentials, file manager data, settings, alerts
- Include OIDC configuration and system settings (admin only)
- Password authentication required for data decryption
- Direct browser download instead of file path display
**Import Features:**
- Incremental import with duplicate detection and skipping
- Smart conflict resolution by key combinations:
- SSH hosts: ip + port + username
- Credentials: name + username
- File manager: path + name
- Re-encrypt imported data to current user's keys
- Admin-only settings import (including OIDC config)
- Detailed import statistics with category breakdown
**Removed:**
- Database backup functionality (redundant with export)
- JSON export format
- File path-based workflows
**Security:**
- Password verification for all operations
- SQLite file format validation
- Proper error handling and logging
- Admin permission checks for settings
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
0506536893