Let admins reorder commitment groups and the cards within each group from
the console Commitments tab using up/down buttons, driven by the existing
rank-aware update mutations.
Make the (parent, rank) unique constraints on the commitment tables
DEFERRABLE INITIALLY DEFERRED. Reordering shifts several rows in one
UPDATE, which transiently duplicates a rank and tripped the immediately
enforced constraint with a 23505 error. This matches the other
rank-ordered tables (references, compliance frameworks).
Signed-off-by: Émile Ré <emile@probo.com>
