- The seeding effect re-applies constants as well as filling absences: an
in-place schema change can move a `const` the user cannot edit, and the
read-only field then displayed the new value while `values` still held the
old one — which is what would be submitted. Ordinary defaults are still only
ever added, so an edited field keeps what the user put there.
- hasMissingIn checks own-property presence: a required argument legally named
`constructor` resolved to the inherited one and read as supplied, enabling
a submit the schema rejects.
- The TUI keeps the declared name as a branch field's fallback title. The
prefix is an internal field NAME, and buildFields labels from its map key —
so the showcase displayed `__b0__address` where the schema says
`address`.
Signed-off-by: cliffhall <cliff@futurescale.com>