The form appeared only when nothing was configured, so once a token was saved
there was no way back to it — a member who mistyped theirs, or anyone rotating
one, had nowhere to go. On a single-user machine that is an annoyance; on a
company one it is the ordinary case, because every member has a token of their
own to set.
Uses the route pair the platform already generates for every plugin, so this
needed no platform change. A plug icon beside the open-in-new-tab button, as a
real Link rather than a button, because it is navigation and should be
cmd-clickable.
Saving returns to the frame — otherwise you are left looking at the form you
just submitted, which reads as nothing having happened.
The two halves were already right: the panel shows only the token field when
isOwner is false, and getResolvedServiceCredentials gives a member the owner's
URL with their OWN secret, never the owner's.