UpdateItem UPDATED_NEW granularity diverges from DynamoDB (nested SET fragment, REMOVE)

[hicksy]

Summary

UpdateItem ReturnValues projection differs from real DynamoDB, surfaced by the dynamodb-conformance suite (Dynoxide 0.9.13).

1. Nested SET. SET parent.child = :v with ReturnValues: UPDATED_NEW should return only the changed fragment, { parent: { M: { child } } }. Dynoxide returns the whole parent map (sibling keys included).
2. REMOVE. REMOVE y with ReturnValues: UPDATED_NEW should omit Attributes entirely, because nothing was set to a new value. Dynoxide returns Attributes: {}.

For reference, UPDATED_NEW on a create already returns the new attributes as AWS does.

[hicksy]

Fixed by #51 — UPDATED_NEW now returns only the changed nested fragment for SET parent.child = :v, and a REMOVE-only update omits Attributes. (Auto-close missed it because the PR said "Closes #35 and #36"; GitHub only honours a closing keyword per issue.)