Support SSH config import and LLM-based connection config generation

[kanyanjp]

onetcli currently requires manual SSH connection setup.

It would be useful to support:

• parsing/importing standard SSH config from ~/.ssh/config
• generating connection config with an LLM from natural language input

For example, users could either reuse an existing Host entry from SSH config, or input something like:

connect to 10.0.0.12 with ubuntu using ~/.ssh/id_rsa

and let the LLM parse it into structured connection settings.

This would reduce manual setup and improve the CLI experience.