Add agents detect command

[mscottford]

agents detect

Used to detect all of the language agents that are available for use.

freshli agents detect

What this command does?

Language agents are detected by searching the $PATH for a program name that starts with freshli-agent-. It is assumed that anything after this prefix is the language name, and would be used whenever referring to the agent that directly.

This command outputs the detected language name and the path to the language agent binary in a tabular format. One line of output is created for each language agent that is detected.

[mscottford]

To help with testing/building this command, there's a skeleton for the Freshli Java Agent that can be installed in your path. You can also create a simple shell script that is named freshli-agent-something. A symbolic link could work, too.