- rootUnion: a `oneOf` demands that EXACTLY one alternative match, which
flattening cannot preserve, so it is offered only when a discriminator makes
the alternatives mutually exclusive; `anyOf` makes no such claim and is
unaffected. An empty `additionalProperties` schema is the equivalent of
`true` and no longer declines a union.
- selectBranchIndex: falls back to the branch whose own required fields the
values supply, so an undiscriminated union's values open the picker on the
shape they describe rather than on the first branch.
- admitsNull: honors a sibling `nullable: true` beside `const: null`.
- SchemaForm: a value is carried only where the incoming branch leaves the
root's declaration as it found it; anything it declares itself is reset,
since it may type the name differently from where the value was typed.
`hasOwn`/`fromEntries` throughout, so `constructor` is not read as a
supplied value and `__proto__` is not dropped into the prototype setter.
- TUI: the same prototype-safe construction on the way out of the form, and
the chosen branch's `required` list is checked at submit — rendering a
branch's fields optional makes the FORM satisfiable, not the call, so the
missing names are reported rather than a known-invalid call being sent.
Signed-off-by: cliffhall <cliff@futurescale.com>
85b8e4601c