claude@clouddev1
827b47f88f
`MatchedKind::Ident` now carries its `IdentSource`. A post-walk pass over a structurally-valid parse flags a matched `Tables` ident that is absent from the schema, or a `Columns` ident absent from the table in scope, as an ERROR diagnostic — the command parses but would fail at execution (ADR-0027 §2). New behaviour: an unknown table / column used to parse cleanly and fail only when run. Column scope is resolved by one left-to-right pass over the matched path (every command places its table ident before the columns that belong to it); an unknown table clears the scope, so its columns are not cascaded into a second diagnostic. New catalog keys `diagnostic.unknown_table` / `diagnostic.unknown_column`.