Extension for testing extensions functionality.

• This exposes the custom command "fs:grep-code".
• This should echo back the API key provided in settings.

• Hoos will be invoked before model calls.
• Should echo a sentence followed by the API key provided by settings.

• Invoke by saying "hello"
• Should respond with a greeting and the API key.

• Exposes a prompt "/poem-writer"
• Exposes a tool "get-key"
• Should add to the system instructions-- confirm by saying 'foo', which should get back 'bar', and then 'soda' should get back 'pop'

• 'new' should get back 'york city'
• 'raindrops' should get back 'on roses'