fix: ADR-0035 4g — reconstruct table-CHECK metadata on rebuild

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).

src/db.rs

@@ -8643,6 +8643,23 @@ fn do_rebuild_from_text(
         ))
         .map_err(DbError::from_rusqlite)?;
 
+        // 0b. The table-level CHECK metadata is the source of truth that
+        //     the engine cannot report (ADR-0035 §4a.3), so — like
+        //     META/REL — it is wiped and repopulated from the YAML
+        //     snapshot here (step 3b). Without this a fresh rebuild
+        //     (missing `.db`) would enforce the CHECK via the recreated
+        //     DDL but leave `CHECK_TABLE` empty, so `describe` / `DROP
+        //     CONSTRAINT` / a later save would lose it. The rebuild also
+        //     **migrates** a pre-§4g table that predates the `name`
+        //     column (the rebuild-only migration, ADR-0035 §4g): add it
+        //     if absent before repopulating with names.
+        if !check_table_has_name_column(&tx)? {
+            tx.execute_batch(&format!("ALTER TABLE {CHECK_TABLE} ADD COLUMN name TEXT;"))
+                .map_err(DbError::from_rusqlite)?;
+        }
+        tx.execute_batch(&format!("DELETE FROM {CHECK_TABLE};"))
+            .map_err(DbError::from_rusqlite)?;
+
         // 1. Recreate user tables with FK constraints inline.
         for table in &snapshot.tables {
             let read_schema = build_read_schema(table, &snapshot.relationships);
@@ -8694,6 +8711,29 @@ fn do_rebuild_from_text(
             }
         }
 
+        // 3b. Table-level CHECK metadata (ADR-0035 §4a.3 / §4g) — in
+        //     declaration order (`seq`), carrying the optional name so a
+        //     named CHECK round-trips through the rebuild.
+        {
+            let mut stmt = tx
+                .prepare(&format!(
+                    "INSERT INTO {CHECK_TABLE} (table_name, seq, check_expr, name) \
+                     VALUES (?1, ?2, ?3, ?4);"
+                ))
+                .map_err(DbError::from_rusqlite)?;
+            for table in &snapshot.tables {
+                for (seq, check) in table.check_constraints.iter().enumerate() {
+                    stmt.execute(rusqlite::params![
+                        table.name,
+                        seq as i64,
+                        check.expr,
+                        check.name,
+                    ])
+                    .map_err(DbError::from_rusqlite)?;
+                }
+            }
+        }
+
         // 4. Project metadata: overwrite the configure-time
         //    `created_at` with the YAML's authoritative value.
         tx.execute(