It would be nice for GitHub mode to just be enabled by default. But in order to avoid problems, we will need to detect if the two key command line tools that enable GitHub mode are available and that gh is authenticated. So if GitHub mode is available (and we should change the default to true), then we check if git and gh are available, and if they are we add encouragement to use them to the system prompts. IF they are not available, but GitHub mode was enabled, we warn the user that they are not available and that GitHub mode should be disabled, or these tools should be installed.