Improve visual cues for TLS verification during cluster bootstrap

I really like the use of colors in the MicroCloud init/join sessions:

However, I think it could still be improved to leverage the brain's natural ability to do color matching. In those 3 terminals, I'd like it if the initiator's fingerprint (`949f00313e81`) could use a different color (blue?).

Also, once the initiator node displays the possible joining candidates, their respective fingerprint should have a color matching the one used when displaying it in the `microcloud join` sessions. I'd propose the joiners' fingerprints to be shown in yellow to avoid any confusion with "selected joiners" that turn the table's line to green:

Start by locating the MicroCloud init and join terminal output that renders node fingerprints. Compare the initiator and candidate displays across bootstrap sessions, then verify that each fingerprint uses a consistent color without confusing the selected-joiner highlighting.

Written by the indexing model from the issue text.