Until now the holder was derived — assigned and claiming — and a second eligible
assignment was refused, so a seat could not pass from one holder to the next
without a moment where nobody held it. The controller finds its own bus through
one of these seats, and that moment took the control plane down on 2026-09-27.
The holder is now a row the controller keeps, written by `seat <name> --to
<node>/<module>` in the same write that removes the previous one. No row means the
old rule, so nothing changes for a mesh that never hands a seat over; with a row,
another eligible assignment is silent rather than refused, which is what lets the
next holder run beside the current one until the switch. A holding is the
assignment's and goes when it does. Each rule names the test that checks it.
Under ADR 0131; design 28 task 5.3 is the work.
jschoubben