50a889e599
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).