Work by: elias, ln5.

This will include getting a metrics dashboard and such setup for jellyfish/seasalp; and this will likely be linked as an example that others can take inspiration from.

https://gitlab.torproject.org/tpo/tpa/team/-/issues/40677 might be a useful reference, good pointers from anarcat wrt. prometheus stuff.

Changes that touch core/ are reviewed by nisse.

Related to this milestone: %Monitoring 2025, phase I (i.e., what elias and ln5 is working on wrt. monitoring / metrics)