The ambient-hint fallback in ambient_hint_core_in_mode parsed
schemalessly, so the type-blind grammar closed an `insert … values
(…)` tuple after the first value and the "Next:" hint pointed at `)`.
With a schema available the walk knows the remaining columns and the
correct next token is `,`. Parse the fallback with the schema cache so
the expected-token prose matches the rest of the (already
schema-aware) hint ladder.
Also corrects wrong-arity closed tuples where the schemaless parse
accepted the input and the hint said "submit with Enter" for a command
the schema-aware parse rejects — the hint now surfaces the accurate
error. Three typing-surface snapshots updated to match.
Docs: ADR-0022 Amendment 3 (+ README index) records the schema-aware
fallback; requirements.md H1a cites the hint-accuracy improvement.