how to install by Manual Installation,don't use opencode install

[Hok1]

As the title says.

[kommander]

You can add it to your tui.json globally or project local in `.opencode/tui.json.

{
  "plugin": ["oc-plugin-rainbow@0.1.1"]
}

It will be downloaded at startup then, using the same logic as the CLI installer. That's basically all the CLI installer does.