claude@clouddev1
90e3f5dbfb
Form C (`insert into T (vals)`) shared the `(` opener with Form A, so its paren was an untyped Repeated(Choice(literal, ident)) — values weren't type- or count-checked at parse time (handoff-12 §2.2). New Node::Lookahead variant: a factory that peeks the source. The insert first-paren factory inspects the first token — a value literal routes the contents through the typed column_value_list (Form B dispatch contract: per-non-auto-column typed slots); an identifier or empty paren routes to a Form A column-name list. So Form C now gets the same per-column typed slots, hints, and parse-time type/count checking Form B has. The explicit-Choice-branch split is impossible here (committed-choice semantics commit after `(` matches); lookahead is the only route, and DynamicSubgrammar factories couldn't see the source. Node::Lookahead is not memoized — its output depends on source — but it returns only a small node (a Repeated, or a thin DynamicSubgrammar wrapper that delegates to the memoized column_value_list). `insert into T (` now cleanly shows Form A column candidates instead of mixed Form-A/C suggestions. Form C matrix tests updated for the type-aware behaviour.