Copilot round 8 opened the same conjunctive-semantics seam a third time, so
this stops patching cases and inverts the defaults instead. Both guards now
fail CLOSED: anything this module cannot evaluate sends the field to the JSON
editor rather than to a widget built from a partial reading.
1. The wrapper-conflict check enumerated the *validation* keywords and declined
when two of them disagreed — which meant any keyword nobody listed
(`oneOf`, `allOf`, `not`, `$ref`, a future vocabulary) was silently treated
as safe to drop. That whitelist fails open, and open means rendering a
widget for a constraint that is not the schema's. It is replaced by an
allowlist of *annotation* keywords: the collapse declines whenever the
wrapper carries anything beyond annotations and the union itself. Stricter
than the old equality test — a wrapper restating its branch's `type` now
declines too — which costs a dropdown on a rare redundant shape and buys a
rule with no gap in it.
2. `admitsNull` returned true for shapes it had not actually evaluated:
`not: { type: "null" }` rules null out, `allOf` can add a member that does,
`oneOf` requires *exactly one* branch to match (so a null branch does not
by itself mean null validates), and a branch like `{ type: "null",
const: "x" }` is unsatisfiable. All now answer false. Under-claiming
nullability costs a clear button; over-claiming lets the form emit a value
the schema rejects, so the asymmetry decides it.
Note the third finding — draft validity never reaching the submit controls —
is NOT fixed here, and it is worse than I described last round: `ToolDetailPanel`
gates Execute on `isExecuting` alone and never calls `hasMissingRequiredFields`,
so my earlier claim that required fields were already covered was wrong for the
Tools tab. Corrected on #2020, which is where the fix belongs.
Signed-off-by: cliffhall <cliff@futurescale.com>