Harvest sweep, batch 1 of 6.
- graph build's unknown-key refusal now parses the op-list element-by-
element and attributes any per-element parse fault as 'op N (kind):',
immune to serde's deny-unknown-fields token position landing on the
following element (RED-first: the misattribution was pinned failing
before the fix).
- the UnsupportedVersion refusal names the full accepted range
('versions 1..=2'), not just the ceiling.
- a bare unresolved type id inside a data-only project now carries the
same Rust-escalation pointer as the namespaced form ('aura nodes new');
outside any project a bare id stays hint-free (a std-name typo is the
likelier cause there).
closes#336
refs #341
claude
6b6086fdef