Add termscp - comprehensive CLI-UI FTP tool

- Add termscp package to home.packages in flake.nix
- Add 'ftp' alias pointing to termscp in zsh.nix
- Update README.md with termscp documentation and usage examples
- Provides rich TUI for FTP/SFTP/SCP/S3/WebDAV file transfers
- Complements existing lftp for scripting vs interactive use

Key features:
- Multi-protocol support (FTP, SFTP, SCP, S3, WebDAV)
- Interactive dual-pane file browser
- Bookmarks and connection management
- File synchronization capabilities
- Customizable themes and interface

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

flake.nix

@@ -46,6 +46,7 @@
         python312Packages.pip
         python312Packages.virtualenv
         lftp
+        termscp
         httpie
         claude-code.packages.aarch64-darwin.claude-code
         nerd-fonts.fira-code