Show class→assoc-family links in the instance view

Show class→assoc-family links in the instance view

Until now the assoc-family edges only appeared in the classes view;
the instance view of, say, BftCrypto would show its families
(BftDSIGN, BftHash, …) only as descendants of the *individual*
fam-instances surfaced for each instance. Add an `assoc` arrow
straight from the focused class node to each entry of
`ciAssocTypes`, so the user can see what families the class
declares without having to find an instance that exercises them.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>