- bash: Add file existence check before reading
- bash: Improve exit code handling for invalid JSON results
- bash: Expand detect_language to support all 42 languages
- python: Use detect_language() instead of non-existent EXT_MAP
- python: Remove exit_on_error param that doesn't exist
- python: Replace read_file test with validate_keys existence check
- Add `un languages [--json]` command to list available execution languages
- Add `un image` command with full image management:
- --list, --info, --delete, --lock, --unlock
- --publish, --visibility, --spawn, --clone
- Update CLI_SPEC.md with new command documentation
- All implementations follow consistent patterns