feat(db): add object table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/db/tests/migrate.rs

@@ -19,6 +19,18 @@ async fn migrate_is_idempotent_and_creates_audit_log(pool: PgPool) {
     assert_eq!(regclass.as_deref(), Some("audit_log"));
 }
 
+#[sqlx::test]
+async fn migrate_creates_object_table(pool: PgPool) {
+    let db = Db::from_pool(pool);
+
+    let regclass: Option<String> = sqlx::query_scalar("SELECT to_regclass('public.object')::text")
+        .fetch_one(db.pool())
+        .await
+        .unwrap();
+
+    assert_eq!(regclass.as_deref(), Some("object"));
+}
+
 #[sqlx::test]
 async fn migrate_creates_vocabulary_and_authority_tables(pool: PgPool) {
     let db = Db::from_pool(pool);