synthetic-undocumented-say expectations (synthetic)

future_undocumented_kind is outside the complete enum in fixed 3.86.0 source. Ordinary text, reasoning and ask already have source/native-sample verification and are no longer rejection examples.

Expected: type/say permits detect=Supported. An unverified say during scanning makes status=pending with no events or cursor advancement and an undocumented_say_kind diagnostic. The next scan rejects again.