skills.md does not expose adding and removing feeds

[nickludlam]

I am guessing the original idea for the workflow has come from using OpenClaw installed natively, where you're sharing the feed subscription state. I've installed OpenClaw inside docker, so I've got no easy way to add or remove blogs to the subscribed feed list.

Could you expand the skills.md file to cover the ability to do this? I think it would be as simple as

feed add feed <url>                     # Add a feed URL
feed remove feed <url>                  # Remove a feed URL
feed get feeds                          # List the current feeds