- branchesKey is built from the resolved alternatives themselves, not from
labels and field names: two branches can share both while pinning different
discriminators or typing a field differently, and a reorder of those went
unnoticed — the form then displayed one branch and submitted another.
- InspectorView gains a deep-link test with root-union appArgs: they name the
second branch, and the assertions pin the picker, the read-only
discriminator, THAT branch's default (not the first branch's), and the
absence of the other branch's field. The old shallow spread fails it.
Signed-off-by: cliffhall <cliff@futurescale.com>
48651956e5