Add terminal in TaskPage #1077

Right now, there is no way to open a terminal directly on the TaskPage. You have to click "view workspace" and from there click "terminal", which opens in either a new window or new tab. This is annoying when you want to run a quick command without necessarily needing to resort to e.g. code-server.

Add "Terminal" as a default iframed workspace app at the end of the app list on the RHS.

As a developer:

• I want to be able to access the workspace terminal easily from the task page so that I can run a quick command.
• In case my web editor dies, I want an easily accessible fallback.

As a citizen developer:

• I may not be familiar with the terminal, so it should not be in my face by default.

As a template administrator:

• When testing out AI template, I want to be able to quickly validate the resulting environment without having to add a bunch of unnecessary workspace apps. A terminal is all I need for this.

This can just be an iframe for now. I explored an implementation here but the terminal is currently a top-level page and not a component.

Note: We should make sure that we preserve the reconnect parameter so that when the user navigates away and back they don't lose their terminal context.