Improved room upgrade flow

[williamkray]

Describe the problem

Currently Cinny doesn't handle room upgrades very well. An upgraded room simply becomes unpostable, with no further information.

Describe the solution you'd like

I would like Cinny to handle providing a link to the replacement room, and linking back to old rooms, similarly to how element handles the upgrade. This allows for a smoother user flow.

Alternatives considered

Currently I just use element if a room upgrade occurs.

Additional context

No response