💡 make app generic between CC members

### Area

None

### What?

- allow users to select their target CC member
- these can be hard coded cold credentials, with human readable names
- using the cold credential, use Koios to find the active hot credential
- we should add some new UI element at the top to support this

### Why?

- this is needed to be able to make the app generic
- this is needed for future features

### How?

- add new UI element with drop down list
- look at how other tools achieve this

Start by locating the existing top-level UI and the current Koios integration. Review how comparable tools select Constitutional Committee members, then add a human-readable dropdown backed by cold credentials and verify that the selected member resolves to its active hot credential.

Written by the indexing model from the issue text.