Add sections in README and installed_software.md explaining that Neovim configuration is available in mg_dotfiles/nvim/ and how to link it manually. Update software list to clarify Neovim is manually installed.
- Update ssh-keyring module to use gcr-ssh-agent.socket instead of gnome-keyring's SSH component
- Configure SSH_AUTH_SOCK to $XDG_RUNTIME_DIR/gcr/ssh
- Merge DOCUMENTACION.md content into Readme.md for unified documentation
- Rename install.md to installed_software.md with updated SSH keyring section
Note: gnome-keyring 46.0+ moved SSH functionality to gcr, requiring gcr-ssh-agent service