Catch rejected onUpdate promises: revert + surface error instead of leaking unhandled rejection

[Copilot]

A throwing async onUpdate escaped handleEdit as an unhandled rejection: the edit was silently lost, edit mode closed as if it succeeded, no error UI rendered, and on newer Node/Jest the rejection terminated the process.

const onUpdate = async () => { throw new Error('boom') }
<JsonEditor data={{ x: 'hello' }} setData={setData} onUpdate={onUpdate} />
// edit + Enter → setData never called, no error shown, unhandledRejection fires

Changes

• src/JsonEditor.tsx — handleEdit: wrap await onUpdateRef.current(input) in try/catch. On rejection, surface err.message (or a bare-string throw) verbatim through the existing error slug, falling back to the event-specific default (ERROR_ADD / ERROR_DELETE / ERROR_UPDATE) — same fallback as the result === false branch.
• No setData on rejection — deliberately matching the existing reject contract (see the comment above the false branch): a slow async rejection must not clobber a newer commit that landed while it was in flight. Display revert is already driven by the node consuming the returned error string, identical to the async-false path.
• test/JsonEditor.test.tsx: promote the #271 test.todo to a real test — throws new Error('boom'), asserts setData is not called, original value still rendered, 'boom' visible in the DOM, and no unhandledRejection fires (regression guard against removing the try/catch).

Behaviour matrix (rejection only — other branches unchanged)

onUpdate outcome	setData	Error shown
throw new Error(m)	no	m
throw 'str'	no	'str'
throw (no message)	no	event-specific default

[github-actions]

Bundle size impact

json-edit-react

Format	Base raw	PR raw	Δ raw	Base gzip	PR gzip	Δ gzip
esm	54.78 KB	54.89 KB	🔺 +119 B (+0.21%)	19.00 KB	19.03 KB	🔺 +32 B (+0.16%)
cjs	56.26 KB	56.37 KB	🔺 +119 B (+0.21%)	19.03 KB	19.05 KB	🔺 +28 B (+0.14%)

_{Measured from build/index.{cjs,esm}.js. Gzip at level 9.}

[CarlosNZ]

Please use the new ERROR_MESSAGE_KEY to correctly map error output strings

[Copilot]

Done — replaced the inline ternary with ERROR_MESSAGE_KEY[input.event] so the rejection fallback now covers rename/move too (ERROR_RENAME/ERROR_MOVE) instead of collapsing them to ERROR_UPDATE.