[FEATURE]: attach feature for `opencode web` command

[OpeOginni]

Feature hasn't been suggested before.

• [x] I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Would be nice to attach a running server to opencode web, noticed that users can also attach to the web app using https://desktop.opencode.ai/?url=<server> but maybe it would be nice to allow for this on the CLI as well.