Feature Request: Add CLI extension toggle capability

[pwgseml]

Currently in the CLI, extensions can only be enabled at session start using flags like --with-extension. It would be valuable to have the ability to toggle extensions on/off during an active session, similar to how the Goose app allows this functionality.

This would improve the CLI experience by:

1. Allowing users to dynamically load extensions as needed without restarting sessions
2. Providing feature parity with the Goose app
3. Making development and testing workflows more efficient
4. Reducing the need to remember all required extensions at session start

Example desired usage:

/extension toggle google-drive  # Toggle specific extension
/extension enable snowflake    # Enable an extension
/extension disable snowflake   # Disable an extension
/extension list               # List available/active extensions

This could be implemented as either slash commands (like the examples above) or as arguments to the existing CLI command system.

[pwgseml]

Possible labels: cli , enhancement

[zakiali]

@pwgseml this actually exists already, but not well documented. In a goose session, if you type /help you'll get a list of the commands that are available. One of them is extension/builtin that operate the same as the --with-extension/builtin cli options