- Add ssh_exec() and ssh_rsync() functions for remote command execution and file transfer with connection pooling
- Add db_import_dns_asset() to import DNS zone records and group by domain with A/AAAA records stored separately
- Add db_import_custom_asset() for flexible JSONL asset import with direct field mapping, supporting tags and custom asset types
- Extend Asset model with ExternalURL, Remarks (string array), Language, Size, and LOC fields for better metadata tracking
- Add backward compatibility layer for legacy JSON formats (string remarks, tags array merging)
- Register new functions in function registry with proper documentation and usage examples