do_rebuild_from_text re-emitted table-level CHECKs into the recreated
DDL (so they stayed enforced) but never repopulated __rdbms_playground_
table_checks. A fresh rebuild (missing .db, reconstructed from
project.yaml) therefore left the CHECK metadata empty: DROP CONSTRAINT,
describe, and a later save would lose it — including a named CHECK's
name. In-place rebuilds only worked because the wipe never touched the
table. (Latent since 4a.3 for unnamed checks; exposed by 4g's named
round-trip claim.)
Rebuild now wipes and repopulates CHECK_TABLE from the yaml snapshot
(name + seq + expr), like META/REL, and adds the 4g `name` column if a
pre-4g table predates it (the rebuild-only migration). Regression test:
a named CHECK's metadata survives a fresh rebuild (DROP CONSTRAINT by
name resolves).