DIS-076: post couples the commit with the branch-advance every commit FFs the tracked branch; post ?/abs/branch mints a bogus ref key (refiles the live half of DIS-061)

Now
DONE

Input

Context

Refiled from DIS-061 STALE its 2026-07-13 rulings cite the deleted trees.mkd and its pin-branch half is overruled by law #4; the commit/advance split and the normalization bug survive verbatim.

Goals

Split the two motions; normalize every branch key through the ONE codec.

Constraints

Every test leg assuming commit==advance moves; that is the expensive part.

WIP

Design decisions

TODOs

Blockers and bummers

Outcome