ADR-0020/0021 specified a chumsky-based H1a; ADR-0024 replaced chumsky
with the scannerless walker, leaving both obsolete. Mark them superseded
(kept as institutional memory) and add ADR-0042, which restates H1a
against the architecture as built.
ADR-0042 records that H1a is substantially shipped already — per-command
usage block, available-commands fallback, source-derived ident slot
labels, curated parse.custom.* near-miss messages, and schema-aware
[ERR] diagnostics — and defines the remaining work: a verified
per-command near-miss matrix (the definition of done), friendlier
literal expectation labels that add role context while keeping the
exact literal visible, and advanced-mode SQL parse parity (RETURNING
scope, CROSS JOIN ON, INSERT…SELECT count), kept distinct from
ADR-0019 §OOS-2 engine-error sanitisation.
- docs/adr/0020,0021: superseded notes + README entries
- docs/adr/0042: new ADR
- docs/adr/README.md: index upkeep (ADR-0000 rule)
claude@clouddev1